diff --git a/data/pine64,pinephone-1.0.toml b/data/pine64,pinephone-1.0.toml
index e1f5b24..8b91a88 100644
--- a/data/pine64,pinephone-1.0.toml
+++ b/data/pine64,pinephone-1.0.toml
@@ -34,22 +34,66 @@ configure = [
 #               match, the command is then executed with value `expect` in
 #               order to set the parameter to the configured value (optional)
 # A command can have `expect` OR `value` configured, but it shouldn't have both
+# Print software version
     { cmd = "QGMR" },
+# Configure audio
     { cmd = "QDAI", expect = "1,1,0,1,0,0,1,1" },
+# RI signaling using physical RI pin
     { cmd = "QCFG", subcmd = "risignaltype", expect = "\"physical\"" },
+# Enable VoLTE support
     { cmd = "QCFG", subcmd = "ims", expect = "1" },
+# Disable APREADY for PP 1.0 because pin is not connected
+    { cmd = "QCFG", subcmd = "apready", expect = "0,0,500" },
+# URC configuration for PP 1.0 (APREADY pin not connected):
+#   * RING URC: extend pulse length
+#   * Incoming SMS URC: extend pulse length
+#   * Other URC: extend pulse length
+#   * Report URCs on all ports (serial and USB) for FOSS firmware
+#   * Delay reporting of URCs
+#   * Configure URC pin to UART Ring Indicator
     { cmd = "QCFG", subcmd = "urc/ri/ring", expect = "\"pulse\",2000,1000,5000,\"off\",1" },
-    { cmd = "QCFG", subcmd = "urc/ri/smsincoming", expect = "\"pulse\",2000" },
-    { cmd = "QCFG", subcmd = "urc/ri/other", expect = "\"off\",1" },
+    { cmd = "QCFG", subcmd = "urc/ri/smsincoming", expect = "\"pulse\",2000,1" },
+    { cmd = "QCFG", subcmd = "urc/ri/other", expect = "\"off\",1,1" },
     { cmd = "QCFG", subcmd = "urc/delay", expect = "1" },
+    { cmd = "QCFG", subcmd = "urc/cache", expect = "0" },
+    { cmd = "QCFG", subcmd = "urc/ri/pin", expect = "uart_ri" },
     { cmd = "QURCCFG", subcmd = "urcport", expect = "\"all\"" },
-    { cmd = "QGPS", value = "1" },
+# Allow sleeping for power saving
     { cmd = "QSCLK", value = "1" },
+# GNSS configuration:
+#   * Enable A-GPS data upload support (XTRA)
+#   * Disable On-Demand-Positioning (ODP) mode 
+#     to avoid running the GNSS system in the background, even when not enabled.
+#   * Enable Dynamic Power Optimizations (DPO) mode to turn off GNSS RF radios 
+#     when they are not in use.
+#   * Only enable GPS and GLONASS, disable other GNSS systems.
+#     A-GPS data upload doesn't work for Galileo anyway.
+#   * Avoid turning on GNSS support automatically when the modem boots.
+    { cmd = "QGPSXTRA", expect = "1" },
+    { cmd = "QGPSCFG", subcmd = "gnssconfig", expect = "4" },
+    { cmd = "QGPSCFG", subcmd = "odpcontrol", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "dpoenable", expect = "1" },
+    { cmd = "QGPSCFG", subcmd = "gpsnmeatype", expect = "31" },
+    { cmd = "QGPSCFG", subcmd = "glonassnmeatype", expect = "7" },
+    { cmd = "QGPSCFG", subcmd = "galileonmeatype", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "beidounmeatype", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "autogps", expect = "0" },
+# Disable fast poweroff for stability
+    { cmd = "QCFG", subcmd = "fast/poweroff", expect = "0" },
+# Configure sleep and wake up pin levels to active low
+    { cmd = "QCFG", subcmd = "sleepind/level", expect = "0" },
+    { cmd = "QCFG", subcmd = "wakeupin/level", expect = "0,0" },
+# Do not enter RAMDUMP mode, auto-reset instead
+    { cmd = "QCFG", subcmd = "ApRstLevel", expect = "1" },
+    { cmd = "QCFG", subcmd = "ModemRstLevel", expect = "1" },
 ]
 suspend = [
-    { cmd = "QGPSEND" },
 ]
 resume = [
-    { cmd = "QGPS", value = "1" }
 ]
 reset = [ { cmd = "CFUN", value = "1,1" } ]
+
+[gnss]
+enabled = true
+url = "https://xtrapath4.izatcloud.net"
+file = "xtra2.bin"
diff --git a/data/pine64,pinephone-1.1.toml b/data/pine64,pinephone-1.1.toml
index e1f5b24..fd09462 100644
--- a/data/pine64,pinephone-1.1.toml
+++ b/data/pine64,pinephone-1.1.toml
@@ -34,22 +34,66 @@ configure = [
 #               match, the command is then executed with value `expect` in
 #               order to set the parameter to the configured value (optional)
 # A command can have `expect` OR `value` configured, but it shouldn't have both
+# Print software version
     { cmd = "QGMR" },
+# Configure audio
     { cmd = "QDAI", expect = "1,1,0,1,0,0,1,1" },
+# RI signaling using physical RI pin
     { cmd = "QCFG", subcmd = "risignaltype", expect = "\"physical\"" },
+# Enable VoLTE support
     { cmd = "QCFG", subcmd = "ims", expect = "1" },
+# Disable APREADY for PP 1.1 because pin is not connected
+    { cmd = "QCFG", subcmd = "apready", expect = "0,0,500" },
+# URC configuration for PP 1.1 (APREADY pin not connected):
+#   * RING URC: extend pulse length
+#   * Incoming SMS URC: extend pulse length
+#   * Other URC: extend pulse length
+#   * Report URCs on all ports (serial and USB) for FOSS firmware
+#   * Delay reporting of URCs
+#   * Configure URC pin to UART Ring Indicator
     { cmd = "QCFG", subcmd = "urc/ri/ring", expect = "\"pulse\",2000,1000,5000,\"off\",1" },
-    { cmd = "QCFG", subcmd = "urc/ri/smsincoming", expect = "\"pulse\",2000" },
-    { cmd = "QCFG", subcmd = "urc/ri/other", expect = "\"off\",1" },
+    { cmd = "QCFG", subcmd = "urc/ri/smsincoming", expect = "\"pulse\",2000,1" },
+    { cmd = "QCFG", subcmd = "urc/ri/other", expect = "\"off\",1,1" },
     { cmd = "QCFG", subcmd = "urc/delay", expect = "1" },
+    { cmd = "QCFG", subcmd = "urc/cache", expect = "0" },
+    { cmd = "QCFG", subcmd = "urc/ri/pin", expect = "uart_ri" },
     { cmd = "QURCCFG", subcmd = "urcport", expect = "\"all\"" },
-    { cmd = "QGPS", value = "1" },
+# Allow sleeping for power saving
     { cmd = "QSCLK", value = "1" },
+# GNSS configuration:
+#   * Enable A-GPS data upload support (XTRA)
+#   * Disable On-Demand-Positioning (ODP) mode 
+#     to avoid running the GNSS system in the background, even when not enabled.
+#   * Enable Dynamic Power Optimizations (DPO) mode to turn off GNSS RF radios 
+#     when they are not in use.
+#   * Only enable GPS and GLONASS, disable other GNSS systems.
+#     A-GPS data upload doesn't work for Galileo anyway.
+#   * Avoid turning on GNSS support automatically when the modem boots.
+    { cmd = "QGPSXTRA", expect = "1" },
+    { cmd = "QGPSCFG", subcmd = "gnssconfig", expect = "4" },
+    { cmd = "QGPSCFG", subcmd = "odpcontrol", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "dpoenable", expect = "1" },
+    { cmd = "QGPSCFG", subcmd = "gpsnmeatype", expect = "31" },
+    { cmd = "QGPSCFG", subcmd = "glonassnmeatype", expect = "7" },
+    { cmd = "QGPSCFG", subcmd = "galileonmeatype", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "beidounmeatype", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "autogps", expect = "0" },
+# Disable fast poweroff for stability
+    { cmd = "QCFG", subcmd = "fast/poweroff", expect = "0" },
+# Configure sleep and wake up pin levels to active low
+    { cmd = "QCFG", subcmd = "sleepind/level", expect = "0" },
+    { cmd = "QCFG", subcmd = "wakeupin/level", expect = "0,0" },
+# Do not enter RAMDUMP mode, auto-reset instead
+    { cmd = "QCFG", subcmd = "ApRstLevel", expect = "1" },
+    { cmd = "QCFG", subcmd = "ModemRstLevel", expect = "1" },
 ]
 suspend = [
-    { cmd = "QGPSEND" },
 ]
 resume = [
-    { cmd = "QGPS", value = "1" }
 ]
 reset = [ { cmd = "CFUN", value = "1,1" } ]
+
+[gnss]
+enabled = true
+url = "https://xtrapath4.izatcloud.net"
+file = "xtra2.bin"
diff --git a/data/pine64,pinephone-1.2.toml b/data/pine64,pinephone-1.2.toml
index 4ca1274..4244bee 100644
--- a/data/pine64,pinephone-1.2.toml
+++ b/data/pine64,pinephone-1.2.toml
@@ -31,19 +31,66 @@ configure = [
 #               match, the command is then executed with value `expect` in
 #               order to set the parameter to the configured value (optional)
 # A command can have `expect` OR `value` configured, but it shouldn't have both
+# Print software version
     { cmd = "QGMR" },
+# Configure audio
     { cmd = "QDAI", expect = "1,1,0,1,0,0,1,1" },
+# RI signaling using physical RI pin
     { cmd = "QCFG", subcmd = "risignaltype", expect = "\"physical\"" },
+# Enable VoLTE support
     { cmd = "QCFG", subcmd = "ims", expect = "1" },
+# Enable APREADY for PP 1.2
     { cmd = "QCFG", subcmd = "apready", expect = "1,0,500" },
+# URC configuration for PP 1.2 (APREADY pin connected):
+#   * RING URC: normal pulse length
+#   * Incoming SMS URC: default pulse length
+#   * Other URC: default length
+#   * Report URCs on all ports (serial and USB) for FOSS firmware
+#   * Reporting of URCs without any delay
+#   * Configure URC pin to UART Ring Indicator
+    { cmd = "QCFG", subcmd = "urc/ri/ring", expect = "\"pulse\",120,1000,5000,\"off\",1" },
+    { cmd = "QCFG", subcmd = "urc/ri/smsincoming", expect = "\"pulse\",120,1" },
+    { cmd = "QCFG", subcmd = "urc/ri/other", expect = "\"off\",1,1" },
+    { cmd = "QCFG", subcmd = "urc/delay", expect = "0" },
+    { cmd = "QCFG", subcmd = "urc/cache", expect = "0" },
+    { cmd = "QCFG", subcmd = "urc/ri/pin", expect = "uart_ri" },
     { cmd = "QURCCFG", subcmd = "urcport", expect = "\"all\"" },
-    { cmd = "QGPS", value = "1" },
+# Allow sleeping for power saving
     { cmd = "QSCLK", value = "1" },
+# GNSS configuration:
+#   * Enable A-GPS data upload support (XTRA)
+#   * Disable On-Demand-Positioning (ODP) mode 
+#     to avoid running the GNSS system in the background, even when not enabled.
+#   * Enable Dynamic Power Optimizations (DPO) mode to turn off GNSS RF radios 
+#     when they are not in use.
+#   * Only enable GPS and GLONASS, disable other GNSS systems.
+#     A-GPS data upload doesn't work for Galileo anyway.
+#   * Avoid turning on GNSS support automatically when the modem boots.
+    { cmd = "QGPSXTRA", expect = "1" },
+    { cmd = "QGPSCFG", subcmd = "gnssconfig", expect = "4" },
+    { cmd = "QGPSCFG", subcmd = "odpcontrol", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "dpoenable", expect = "1" },
+    { cmd = "QGPSCFG", subcmd = "gpsnmeatype", expect = "31" },
+    { cmd = "QGPSCFG", subcmd = "glonassnmeatype", expect = "7" },
+    { cmd = "QGPSCFG", subcmd = "galileonmeatype", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "beidounmeatype", expect = "0" },
+    { cmd = "QGPSCFG", subcmd = "autogps", expect = "0" },
+# Disable fast poweroff for stability
+    { cmd = "QCFG", subcmd = "fast/poweroff", expect = "0" },
+# Configure sleep and wake up pin levels to active low
+    { cmd = "QCFG", subcmd = "sleepind/level", expect = "0" },
+    { cmd = "QCFG", subcmd = "wakeupin/level", expect = "0,0" },
+# Do not enter RAMDUMP mode, auto-reset instead
+    { cmd = "QCFG", subcmd = "ApRstLevel", expect = "1" },
+    { cmd = "QCFG", subcmd = "ModemRstLevel", expect = "1" },
 ]
 suspend = [
-    { cmd = "QGPSEND" },
 ]
 resume = [
-    { cmd = "QGPS", value = "1" }
 ]
 reset = [ { cmd = "CFUN", value = "1,1" } ]
+
+[gnss]
+enabled = true
+url = "https://xtrapath4.izatcloud.net"
+file = "xtra2.bin"
diff --git a/meson.build b/meson.build
index d57d2cb..fbbbf64 100644
--- a/meson.build
+++ b/meson.build
@@ -8,7 +8,7 @@
 project (
   'eg25-manager',
   'c',
-  version : '0.3.0',
+  version : '0.4.0',
   license : 'GPLv3+',
   meson_version : '>= 0.50.0',
   default_options :
@@ -58,6 +58,7 @@ mgr_deps = [
     dependency('gudev-1.0'),
     dependency('libgpiod'),
     dependency('libusb-1.0'),
+    dependency('libcurl'),
     mmglib_dep,
 ]
 
diff --git a/src/at.c b/src/at.c
index a34025f..228ded6 100644
--- a/src/at.c
+++ b/src/at.c
@@ -6,6 +6,8 @@
 
 #include "at.h"
 #include "suspend.h"
+#include "gpio.h"
+#include "gnss.h"
 
 #include <fcntl.h>
 #include <stdio.h>
@@ -16,14 +18,6 @@
 
 #include <glib-unix.h>
 
-struct AtCommand {
-    char *cmd;
-    char *subcmd;
-    char *value;
-    char *expected;
-    int retries;
-};
-
 static GArray *configure_commands = NULL;
 static GArray *suspend_commands = NULL;
 static GArray *resume_commands = NULL;
@@ -52,13 +46,17 @@ static int configure_serial(const char *tty)
     return fd;
 }
 
-static gboolean send_at_command(struct EG25Manager *manager)
+gboolean at_send_command(struct EG25Manager *manager)
 {
     char command[256];
     struct AtCommand *at_cmd = manager->at_cmds ? g_list_nth_data(manager->at_cmds, 0) : NULL;
     int ret, len = 0;
 
     if (at_cmd) {
+    	/* Wake up the modem from soft sleep before sending an AT command */
+    	gpio_sequence_wake(manager);
+
+	/* Send AT command */
         if (at_cmd->subcmd == NULL && at_cmd->value == NULL && at_cmd->expected == NULL)
             len = sprintf(command, "AT+%s\r\n", at_cmd->cmd);
         else if (at_cmd->subcmd == NULL && at_cmd->value == NULL)
@@ -69,53 +67,55 @@ static gboolean send_at_command(struct EG25Manager *manager)
             len = sprintf(command, "AT+%s=\"%s\"\r\n", at_cmd->cmd, at_cmd->subcmd);
         else if (at_cmd->subcmd && at_cmd->value)
             len = sprintf(command, "AT+%s=\"%s\",%s\r\n", at_cmd->cmd, at_cmd->subcmd, at_cmd->value);
+        manager->at_callback = at_cmd->callback;
 
         ret = write(manager->at_fd, command, len);
         if (ret < len)
             g_warning("Couldn't write full AT command: wrote %d/%d bytes", ret, len);
 
         g_message("Sending command: %s", g_strstrip(command));
-    } else if (manager->modem_state < EG25_STATE_CONFIGURED) {
-        if (manager->modem_iface == MODEM_IFACE_MODEMMANAGER) {
+    } else {
+    	/* Allow the modem to enter soft sleep again when we sent the AT command*/
+    	gpio_sequence_sleep(manager);
+	
+	if (manager->modem_state < EG25_STATE_CONFIGURED) {
+	    if (manager->modem_iface == MODEM_IFACE_MODEMMANAGER) {
 #ifdef HAVE_MMGLIB
-            MMModemState modem_state = mm_modem_get_state(manager->mm_modem);
+                MMModemState modem_state = mm_modem_get_state(manager->mm_modem);
 
-            if (manager->mm_modem && modem_state >= MM_MODEM_STATE_REGISTERED)
-                modem_update_state(manager, modem_state);
-            else
-                manager->modem_state = EG25_STATE_CONFIGURED;
+		if (manager->mm_modem && modem_state >= MM_MODEM_STATE_REGISTERED)
+                    modem_update_state(manager, modem_state);
+		else
+                    manager->modem_state = EG25_STATE_CONFIGURED;
 #endif
-        } else {
-            manager->modem_state = EG25_STATE_CONFIGURED;
+            } else {
+                manager->modem_state = EG25_STATE_CONFIGURED;
+	    }
+        } else if (manager->modem_state == EG25_STATE_SUSPENDING) {
+            modem_suspend_post(manager);
+        } else if (manager->modem_state == EG25_STATE_RESETTING) {
+            manager->modem_state = EG25_STATE_POWERED;
         }
-    } else if (manager->modem_state == EG25_STATE_SUSPENDING) {
-        modem_suspend_post(manager);
-    } else if (manager->modem_state == EG25_STATE_RESETTING) {
-        manager->modem_state = EG25_STATE_POWERED;
     }
 
     return FALSE;
 }
 
-static void next_at_command(struct EG25Manager *manager)
+void at_next_command(struct EG25Manager *manager)
 {
     struct AtCommand *at_cmd = manager->at_cmds ? g_list_nth_data(manager->at_cmds, 0) : NULL;
 
     if (!at_cmd)
         return;
 
-    if (at_cmd->cmd)
-        g_free(at_cmd->cmd);
-    if (at_cmd->subcmd)
-        g_free(at_cmd->subcmd);
-    if (at_cmd->value)
-        g_free(at_cmd->value);
-    if (at_cmd->expected)
-        g_free(at_cmd->expected);
+    g_free(at_cmd->cmd);
+    g_free(at_cmd->subcmd);
+    g_free(at_cmd->value);
+    g_free(at_cmd->expected);
     g_free(at_cmd);
     manager->at_cmds = g_list_remove(manager->at_cmds, at_cmd);
 
-    send_at_command(manager);
+    at_send_command(manager);
 }
 
 static void retry_at_command(struct EG25Manager *manager)
@@ -128,13 +128,14 @@ static void retry_at_command(struct EG25Manager *manager)
     at_cmd->retries++;
     if (at_cmd->retries > 3) {
         g_critical("Command %s retried %d times, aborting...", at_cmd->cmd, at_cmd->retries);
-        next_at_command(manager);
+        at_next_command(manager);
     } else {
-        g_timeout_add(500, G_SOURCE_FUNC(send_at_command), manager);
+        g_timeout_add(500, G_SOURCE_FUNC(at_send_command), manager);
     }
 }
 
-static void process_at_result(struct EG25Manager *manager, char *response)
+void at_process_result(struct EG25Manager *manager,
+                       const char         *response)
 {
     struct AtCommand *at_cmd = manager->at_cmds ? g_list_nth_data(manager->at_cmds, 0) : NULL;
 
@@ -142,23 +143,25 @@ static void process_at_result(struct EG25Manager *manager, char *response)
         return;
 
     if (at_cmd->expected && !strstr(response, at_cmd->expected)) {
-        if (at_cmd->value)
-            g_free(at_cmd->value);
+        g_free(at_cmd->value);
         at_cmd->value = at_cmd->expected;
-        at_cmd->expected = NULL;
         g_message("Got a different result than expected, changing value...");
-        g_message("\t%s\n\t%s", at_cmd->expected, response);
-        send_at_command(manager);
+        g_message("Expected: [%s]\nResponse: [%s]", at_cmd->expected, response);
+        at_cmd->expected = NULL;
+        at_send_command(manager);
     } else {
-        next_at_command(manager);
+        at_next_command(manager);
     }
 }
 
-static int append_at_command(struct EG25Manager *manager,
-                             const char         *cmd,
-                             const char         *subcmd,
-                             const char         *value,
-                             const char         *expected)
+int at_append_command(struct EG25Manager *manager,
+                      const char         *cmd,
+                      const char         *subcmd,
+                      const char         *value,
+                      const char         *expected,
+                      void              (*callback)
+                                        (struct EG25Manager *manager,
+                                         const char *response))
 {
     struct AtCommand *at_cmd = calloc(1, sizeof(struct AtCommand));
 
@@ -172,6 +175,8 @@ static int append_at_command(struct EG25Manager *manager,
         at_cmd->value = g_strdup(value);
     if (expected)
         at_cmd->expected = g_strdup(expected);
+    if (callback)
+        at_cmd->callback = callback;
 
     manager->at_cmds = g_list_append(manager->at_cmds, at_cmd);
 
@@ -211,17 +216,42 @@ static gboolean modem_response(gint fd,
 
         g_message("Response: [%s]", response);
 
+        /*
+         * When the modem is started, it outputs 'RDY' to indicate that
+         * it is ready to receive AT commands.
+         */
         if (strcmp(response, "RDY") == 0) {
             suspend_inhibit(manager, TRUE, TRUE);
             manager->modem_state = EG25_STATE_STARTED;
         }
-        else if (strstr(response, "ERROR"))
+        /*
+         * Search for 'QGPSURC: "xtradataexpire"' in response to detect
+         * if GNSS assistance data must be re-uploaded.
+         * If that's the case, check if no AT commands are being processed
+         * to avoid deadlocks and start upload.
+         */
+        else if (strstr(response, "QGPSURC: \"xtradataexpire\"") && manager->at_cmds == NULL)
+            gnss_upload_assistance_data(manager);
+        /*
+         * AT command failed, retry.
+         * QCFG="fast/poweroff" configuration is only available in
+         * newer firmware versions, skip retrying that specific AT command.
+         */
+        else if (strstr(response, "ERROR") && !strstr(response, "fast/poweroff"))
             retry_at_command(manager);
-        else if (strstr(response, "OK"))
-            process_at_result(manager, response);
+        /*
+         * Successfull AT responses contain 'OK', except for AT+QFUPL which also
+         * returns 'CONNECT' when the modem is ready to receive data over serial
+         */
+        else if (strstr(response, "OK") || strstr(response, "CONNECT")) {
+            if (manager->at_callback != NULL)
+                manager->at_callback(manager, response);
+            else
+                g_warning("AT command succesfull but no callback registered");
+        }
+        /* Not a recognized response, try running next command, just in case */
         else
-            // Not a recognized response, try running next command, just in case
-            next_at_command(manager);
+            at_next_command(manager);
     }
 
     return TRUE;
@@ -326,34 +356,34 @@ void at_sequence_configure(struct EG25Manager *manager)
 {
     for (guint i = 0; i < configure_commands->len; i++) {
         struct AtCommand *cmd = &g_array_index(configure_commands, struct AtCommand, i);
-        append_at_command(manager, cmd->cmd, cmd->subcmd, cmd->value, cmd->expected);
+        at_append_command(manager, cmd->cmd, cmd->subcmd, cmd->value, cmd->expected, at_process_result);
     }
-    send_at_command(manager);
+    at_send_command(manager);
 }
 
 void at_sequence_suspend(struct EG25Manager *manager)
 {
     for (guint i = 0; i < suspend_commands->len; i++) {
         struct AtCommand *cmd = &g_array_index(suspend_commands, struct AtCommand, i);
-        append_at_command(manager, cmd->cmd, cmd->subcmd, cmd->value, cmd->expected);
+        at_append_command(manager, cmd->cmd, cmd->subcmd, cmd->value, cmd->expected, at_process_result);
     }
-    send_at_command(manager);
+    at_send_command(manager);
 }
 
 void at_sequence_resume(struct EG25Manager *manager)
 {
     for (guint i = 0; i < resume_commands->len; i++) {
         struct AtCommand *cmd = &g_array_index(resume_commands, struct AtCommand, i);
-        append_at_command(manager, cmd->cmd, cmd->subcmd, cmd->value, cmd->expected);
+        at_append_command(manager, cmd->cmd, cmd->subcmd, cmd->value, cmd->expected, at_process_result);
     }
-    send_at_command(manager);
+    at_send_command(manager);
 }
 
 void at_sequence_reset(struct EG25Manager *manager)
 {
     for (guint i = 0; i < reset_commands->len; i++) {
         struct AtCommand *cmd = &g_array_index(reset_commands, struct AtCommand, i);
-        append_at_command(manager, cmd->cmd, cmd->subcmd, cmd->value, cmd->expected);
+        at_append_command(manager, cmd->cmd, cmd->subcmd, cmd->value, cmd->expected, at_process_result);
     }
-    send_at_command(manager);
+    at_send_command(manager);
 }
diff --git a/src/at.h b/src/at.h
index ba294a4..0364e2c 100644
--- a/src/at.h
+++ b/src/at.h
@@ -8,10 +8,32 @@
 
 #include "manager.h"
 
-int at_init(struct EG25Manager *data, toml_table_t *config);
-void at_destroy(struct EG25Manager *data);
+typedef struct AtCommand {
+    char *cmd;
+    char *subcmd;
+    char *value;
+    char *expected;
+    void (*callback)(struct EG25Manager *manager, const char *response);
+    int retries;
+} AtCommand;
 
-void at_sequence_configure(struct EG25Manager *data);
-void at_sequence_suspend(struct EG25Manager *data);
-void at_sequence_resume(struct EG25Manager *data);
-void at_sequence_reset(struct EG25Manager *data);
+int at_init(struct EG25Manager *manager, toml_table_t *config);
+void at_destroy(struct EG25Manager *manager);
+
+void at_process_result(struct EG25Manager *manager,
+                       const char         *response);
+void at_next_command(struct EG25Manager *manager);
+gboolean at_send_command(struct EG25Manager *manager);
+int at_append_command(struct EG25Manager *manager,
+                      const char         *cmd,
+                      const char         *subcmd,
+                      const char         *value,
+                      const char         *expected,
+                      void              (*callback)
+                                        (struct EG25Manager *manager,
+                                         const char *response));
+
+void at_sequence_configure(struct EG25Manager *manager);
+void at_sequence_suspend(struct EG25Manager *manager);
+void at_sequence_resume(struct EG25Manager *manager);
+void at_sequence_reset(struct EG25Manager *manager);
diff --git a/src/gnss.c b/src/gnss.c
new file mode 100644
index 0000000..aeb73af
--- /dev/null
+++ b/src/gnss.c
@@ -0,0 +1,488 @@
+/*
+ * Copyright (C) 2021 Dylan Van Assche <me@dylanvanassche.be>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include "gnss.h"
+#include "manager.h"
+#include "at.h"
+
+#define BUFFER_SIZE 256
+#define UPLOAD_DELAY 100000
+#define RESCHEDULE_IN_SECS 30
+
+static void gnss_step(struct EG25Manager *manager);
+
+gboolean gnss_upload_assistance_data(struct EG25Manager *manager)
+{
+    if (!manager->gnss_assistance_enabled) {
+        g_message("GNSS assistance is disabled!");
+        return FALSE;
+    }
+
+    if (manager->gnss_assistance_step < EG25_GNSS_STEP_LAST) {
+        g_warning("GNSS assistance data upload already in process (%d/%d)",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        return FALSE;
+    }
+
+    /* ModemManager's Location is only available after unlocking */
+    if(!manager->mm_location) {
+        g_message ("Rescheduling upload since Location interface is not available, in %ds",
+                   RESCHEDULE_IN_SECS);
+        manager->gnss_assistance_step = EG25_GNSS_STEP_LAST;
+        return TRUE;
+    }
+
+    manager->gnss_assistance_step = EG25_GNSS_STEP_FIRST;
+    gnss_step(manager);
+    return FALSE;
+}
+
+void gnss_init(struct EG25Manager *manager, toml_table_t *config)
+{
+    toml_datum_t enabled;
+    toml_datum_t url;
+    toml_datum_t file;
+    g_autoptr (GError) error = NULL;
+
+    /*
+     * GNSS assistance is an optional feature, you can disable it
+     * if you want in the configuration file.
+     * In case the configuration is missing, we assume GNSS assistance
+     * to be disabled.
+     */
+    enabled = toml_bool_in(config, "enabled");
+    manager->gnss_assistance_enabled = FALSE;
+    if (enabled.ok)
+        manager->gnss_assistance_enabled = enabled.u.b;
+
+    if (!manager->gnss_assistance_enabled) {
+        g_message("GNSS assistance is disabled!");
+        return;
+    }
+
+    url = toml_string_in(config, "url");
+    if (url.ok)
+        manager->gnss_assistance_url = url.u.s;
+    else
+        g_error("GNSS assistance server URL is missing from config file");
+    file = toml_string_in(config, "file");
+    if (file.ok)
+        manager->gnss_assistance_file = file.u.s;
+    else
+        g_error("GNSS assistance file name is missing from config file");
+
+    /* Create temporary file to store assistance data */
+    manager->gnss_assistance_fd = g_file_open_tmp(NULL, NULL, &error);
+    if (error != NULL)
+        g_error ("Unable to create temporary file: %s", error->message);
+
+    /* Initialize state and schedule upload */
+    manager->gnss_assistance_step = EG25_GNSS_STEP_LAST;
+    g_timeout_add_seconds(RESCHEDULE_IN_SECS,
+                          G_SOURCE_FUNC(gnss_upload_assistance_data), manager);
+}
+
+void gnss_destroy(struct EG25Manager *manager)
+{
+    close(manager->gnss_assistance_fd);
+}
+
+/******************************************************************************/
+
+#ifdef HAVE_MMGLIB
+static void disable_mm_gnss(struct EG25Manager *manager)
+{
+    MMModemLocationSource sources;
+    gboolean signals_location;
+    g_autoptr (GError) error = NULL;
+
+    sources = mm_modem_location_get_enabled(manager->mm_location);
+    signals_location = mm_modem_location_signals_location(manager->mm_location);
+    manager->gnss_sources = EG25_GNSS_SOURCE_NONE;
+
+    /* Save GNSS engine state */
+    if (sources & MM_MODEM_LOCATION_SOURCE_GPS_NMEA)
+        manager->gnss_sources |= EG25_GNSS_SOURCE_NMEA;
+    else
+        manager->gnss_sources &= ~EG25_GNSS_SOURCE_NMEA;
+
+    if (sources & MM_MODEM_LOCATION_SOURCE_GPS_RAW)
+        manager->gnss_sources |= EG25_GNSS_SOURCE_RAW;
+    else
+        manager->gnss_sources &= ~EG25_GNSS_SOURCE_RAW;
+
+    if (sources & MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED)
+        manager->gnss_sources |= EG25_GNSS_SOURCE_UNMANAGED;
+    else
+        manager->gnss_sources &= ~EG25_GNSS_SOURCE_UNMANAGED;
+
+    /* Disable GNSS engine */
+    sources &= ~MM_MODEM_LOCATION_SOURCE_GPS_RAW;
+    sources &= ~MM_MODEM_LOCATION_SOURCE_GPS_NMEA;
+    sources &= ~MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED;
+    mm_modem_location_setup_sync(manager->mm_location, sources,
+                                 signals_location, NULL, &error);
+    if (error != NULL) {
+        g_warning("Unable to disable GNSS engine through ModemManager: %s",
+                  error->message);
+    }
+}
+#endif
+
+static void disable_at_gnss_cb(struct EG25Manager *manager,
+                               const char *response)
+{
+    /* Clear QGPSEND AT command and process next */
+    at_next_command(manager);
+
+    /* Go to the next step */
+    manager->gnss_assistance_step++;
+    gnss_step(manager);
+}
+
+static void state_at_gnss_cb(struct EG25Manager *manager, const char *response)
+{
+    struct AtCommand *at_cmd = manager->at_cmds ? g_list_nth_data(manager->at_cmds, 0) : NULL;
+
+    if (!at_cmd)
+        return;
+
+    /* Parse GNSS engine status and disable it if needed */
+    if (strstr(response, "QGPS: 1")) {
+        manager->gnss_sources |= EG25_GNSS_SOURCE_QGPS;
+        g_free(at_cmd->value);
+        g_free(at_cmd->cmd);
+        at_cmd->expected = NULL;
+        at_cmd->subcmd = NULL;
+        at_cmd->value = NULL;
+        at_cmd->cmd = g_strdup("QGPSEND");
+        at_cmd->callback = disable_at_gnss_cb;
+        at_send_command(manager);
+    }
+    /* QGPS is already disabled, move on to next step */
+    else {
+        at_next_command(manager);
+        manager->gnss_sources &= ~EG25_GNSS_SOURCE_QGPS;
+        manager->gnss_assistance_step++;
+        gnss_step(manager);
+    }
+}
+
+static void state_at_gnss(struct EG25Manager *manager)
+{
+    /* Asynchronously send AT command to query status of GNSS engine */
+    at_append_command(manager, "QGPS?", NULL, NULL, NULL, state_at_gnss_cb);
+    at_send_command(manager);
+}
+
+/******************************************************************************/
+
+static void fetch_assistance_data(struct EG25Manager *manager)
+{
+    CURL *curl;
+    CURLcode response;
+    long status_code;
+    gchar *url = NULL;
+    FILE *tmp_file = NULL;
+    long int size;
+
+    /* Fetch assistance data with curl */
+    tmp_file = fdopen(manager->gnss_assistance_fd, "wb");
+    url = g_strconcat(manager->gnss_assistance_url, "/",
+                      manager->gnss_assistance_file, NULL);
+    curl = curl_easy_init();
+    if (!curl)
+        g_error ("Unable to initialize curl");
+    curl_easy_setopt(curl, CURLOPT_URL, url);
+    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, NULL);
+    curl_easy_setopt(curl, CURLOPT_WRITEDATA, tmp_file);
+    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
+    curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1L);
+    response = curl_easy_perform(curl);
+    if (response == CURLE_HTTP_RETURNED_ERROR) {
+        curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &status_code);
+        curl_easy_cleanup(curl);
+        g_warning ("Unable to fetch GNSS assistance data from %s (HTTP %ld)",
+                   url, status_code);
+
+        /* Restart upload on HTTP error status code */
+        g_message ("Rescheduling upload because of failure in %ds",
+                   RESCHEDULE_IN_SECS);
+        manager->gnss_assistance_step = EG25_GNSS_STEP_LAST;
+        g_timeout_add_seconds(RESCHEDULE_IN_SECS,
+                              G_SOURCE_FUNC(gnss_upload_assistance_data),
+                              manager);
+        return;
+    }
+
+    /* Get file size in bytes */
+    size = (long int)lseek(manager->gnss_assistance_fd, 0, SEEK_END);
+    lseek(manager->gnss_assistance_fd, 0, SEEK_SET);
+
+    if (size <= 0) {
+        g_warning ("GNSS assistance data contains 0 bytes,"
+                   "check network connection.");
+        /*
+         * Restart upload when file does not contain any data,
+         * mostly because of no network connection.
+         */
+        g_message ("Rescheduling upload because of failure in %ds",
+                   RESCHEDULE_IN_SECS);
+        manager->gnss_assistance_step = EG25_GNSS_STEP_LAST;
+        g_timeout_add_seconds(RESCHEDULE_IN_SECS,
+                              G_SOURCE_FUNC(gnss_upload_assistance_data),
+                              manager);
+        return;
+    }
+
+    g_message("Fetching GNSS assistance data from %s was successfull", url);
+    curl_easy_cleanup(curl);
+    g_free(url);
+
+    /* Go to the next step */
+    manager->gnss_assistance_step++;
+    gnss_step(manager);
+}
+
+/******************************************************************************/
+
+static void init_assistance_data_upload_ready(struct EG25Manager *manager,
+                                              const char *response)
+{
+    /* Search for 'CONNECT' in response to start upload */
+    if (strstr(response, "CONNECT")) {
+        g_message("Modem ready for GNSS assistance data upload");
+        manager->gnss_assistance_step++;
+        gnss_step(manager);
+    }
+}
+
+static void init_assistance_data_upload_start(struct EG25Manager *manager,
+                                              const char *response)
+{
+    gchar value[BUFFER_SIZE];
+    long int size;
+
+    /* Process AT response */
+    at_process_result(manager, response);
+
+    /* Get file size in bytes */
+    size = (long int)lseek(manager->gnss_assistance_fd, 0, SEEK_END);
+    lseek(manager->gnss_assistance_fd, 0, SEEK_SET);
+
+    /* Start upload */
+    g_snprintf(value, BUFFER_SIZE, "\"RAM:%s\",%ld\r\n",
+               manager->gnss_assistance_file, size);
+    g_message("Initiate GNSS assistance data upload: %s", value);
+    at_append_command(manager, "QFUPL", NULL, value, NULL,
+                      init_assistance_data_upload_ready);
+    at_send_command(manager);
+}
+
+static void init_assistance_data_upload(struct EG25Manager *manager)
+{
+    /*
+     * Delete all previous GNSS assistance data files in RAM
+     * and start uploading the latest one to RAM.
+     */
+    at_append_command(manager, "QFDEL", NULL, "\"RAM:*\"\r\n",
+                         NULL, init_assistance_data_upload_start);
+    at_send_command(manager);
+}
+
+static void upload_assistance_data(struct EG25Manager *manager)
+{
+    char buffer[2*BUFFER_SIZE];
+    gint len;
+    gboolean success = TRUE;
+
+    /* Copy downloaded XTRA assistance data to the modem over serial */
+    while((len = read(manager->gnss_assistance_fd, buffer, 2*BUFFER_SIZE)) > 0)
+    {
+        len = write(manager->at_fd, buffer, len);
+        if (len < 0) {
+            success = FALSE;
+            g_error("Writing GNSS assistance data failed: %d", len);
+            break;
+        }
+        usleep(UPLOAD_DELAY);
+        g_message("Uploaded %d bytes", len);
+    }
+
+    /* Clear QFUPL AT command and process next */
+    at_next_command(manager);
+
+    /* Go to the next step if successful */
+    if (success) {
+        manager->gnss_assistance_step++;
+        gnss_step(manager);
+    }
+    /* Restart upload */
+    else {
+        g_message ("Rescheduling upload because of failure in %ds",
+                   RESCHEDULE_IN_SECS);
+        manager->gnss_assistance_step = EG25_GNSS_STEP_LAST;
+        g_timeout_add_seconds(RESCHEDULE_IN_SECS,
+                              G_SOURCE_FUNC(gnss_upload_assistance_data),
+                              manager);
+    }
+}
+
+static void finish_assistance_data_upload_cb(struct EG25Manager *manager,
+                                             const char *response)
+{
+    /* Process response */
+    at_process_result(manager, response);
+    g_message("GNSS assistance data upload finished");
+
+    /* Go to the next step */
+    manager->gnss_assistance_step++;
+    gnss_step(manager);
+}
+
+static void finish_assistance_data_upload(struct EG25Manager *manager)
+{
+    gchar value[BUFFER_SIZE];
+    GDateTime *datetime;
+    gchar *timestring;
+
+    /* Configure GNSS assistance clock to current system time (UTC) */
+    datetime = g_date_time_new_now_utc();
+    timestring = g_date_time_format(datetime, "0,\"%Y/%m/%d,%H:%M:%S\"\r\n");
+    g_message("Setting GNSS assistance UTC clock to: %s", timestring);
+    at_append_command(manager, "QGPSXTRATIME", NULL, timestring, NULL,
+                         at_process_result);
+
+    /* Configure GNSS engine to use uploaded GNSS assistance data */
+    g_snprintf(value, BUFFER_SIZE, "\"RAM:%s\"\r\n",
+               manager->gnss_assistance_file);
+    g_message("Setting GNSS assistance file to: %s", value);
+    at_append_command(manager, "QGPSXTRADATA", NULL, value, NULL,
+                         finish_assistance_data_upload_cb);
+    at_send_command(manager);
+}
+
+/******************************************************************************/
+
+#ifdef HAVE_MMGLIB
+static void enable_mm_gnss(struct EG25Manager *manager)
+{
+    MMModemLocationSource sources;
+    gboolean signal_location;
+    g_autoptr (GError) error = NULL;
+
+    if (manager->gnss_sources & EG25_GNSS_SOURCE_UNMANAGED)
+        sources |= MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED;
+    if (manager->gnss_sources & EG25_GNSS_SOURCE_NMEA)
+        sources |= MM_MODEM_LOCATION_SOURCE_GPS_NMEA;
+    if (manager->gnss_sources & EG25_GNSS_SOURCE_RAW)
+        sources |= MM_MODEM_LOCATION_SOURCE_GPS_RAW;
+
+    sources = mm_modem_location_get_enabled(manager->mm_location);
+    signal_location = mm_modem_location_signals_location(manager->mm_location);
+    mm_modem_location_setup_sync(manager->mm_location, sources,
+                                 signal_location, NULL, &error);
+    if (error != NULL)
+        g_warning("Unable to enable GNSS engine through ModemManager: %s",
+                  error->message);
+}
+#endif
+
+static void enable_at_gnss_cb(struct EG25Manager *manager, const char *response)
+{
+    manager->gnss_assistance_step++;
+    gnss_step(manager);
+}
+
+static void enable_at_gnss(struct EG25Manager *manager)
+{
+    if (manager->gnss_sources & EG25_GNSS_SOURCE_QGPS) {
+        at_append_command(manager, "QGPS", NULL, "1", NULL,
+                             enable_at_gnss_cb);
+        at_send_command(manager);
+        return;
+    }
+    manager->gnss_assistance_step++;
+    gnss_step(manager);
+}
+
+/******************************************************************************/
+
+void gnss_step(struct EG25Manager *manager)
+{
+    switch(manager->gnss_assistance_step) {
+    case EG25_GNSS_STEP_FIRST:
+        manager->gnss_assistance_step++;
+        g_message("GNSS assistance upload started...");
+        /* fall-through */
+
+#ifdef HAVE_MMGLIB
+    case EG25_GNSS_STEP_MM_GNSS_DISABLE:
+        g_message("GNSS assistance upload step (%d/%d): "
+                  "disabling GNSS engine through ModemManager",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        disable_mm_gnss(manager);
+        manager->gnss_assistance_step++;
+        /* fall-through */
+#endif
+
+    case EG25_GNSS_STEP_AT_GNSS_DISABLE:
+        g_message("GNSS assistance upload step (%d/%d): "
+                  "disabling GNSS engine through AT+QGPS",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        state_at_gnss(manager);
+        break;
+
+    case EG25_GNSS_STEP_FETCH_ASSISTANCE_DATA:
+        g_message("GNSS assistance upload step (%d/%d): "
+                  "fetching assistance data",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        fetch_assistance_data(manager);
+        break;
+
+    case EG25_GNSS_STEP_INIT_UPLOAD:
+        g_message("GNSS assistance upload step (%d/%d): initiating upload",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        init_assistance_data_upload(manager);
+        break;
+
+    case EG25_GNSS_STEP_UPLOAD:
+        g_message("GNSS assistance upload step (%d/%d): "
+                  "uploading assistance data",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        upload_assistance_data(manager);
+        break;
+
+    case EG25_GNSS_STEP_FINISH_UPLOAD:
+        g_message("GNSS assistance upload step (%d/%d): finishing upload",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        finish_assistance_data_upload(manager);
+        break;
+
+#ifdef HAVE_MMGLIB
+    case EG25_GNSS_STEP_MM_GNSS_ENABLE:
+        g_message("GNSS assistance upload step (%d/%d): "
+                  "re-enabling GNSS through ModemManager",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        enable_mm_gnss(manager);
+        manager->gnss_assistance_step++;
+        /* fall-through */
+#endif
+
+    case EG25_GNSS_STEP_AT_QGPS_ENABLE:
+        g_message("GNSS assistance upload step (%d/%d): "
+                  "re-enabling GNSS through AT+QGPS",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        enable_at_gnss(manager);
+        break;
+
+    case EG25_GNSS_STEP_LAST:
+        g_message("GNSS assistance upload step (%d/%d): finished",
+                  manager->gnss_assistance_step, EG25_GNSS_STEP_LAST);
+        break;
+    }
+}
+
diff --git a/src/gnss.h b/src/gnss.h
new file mode 100644
index 0000000..1b49403
--- /dev/null
+++ b/src/gnss.h
@@ -0,0 +1,16 @@
+/*
+ * Copyright (C) 2021 Dylan Van Assche <me@dylanvanassche.be>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include <time.h>
+#include <curl/curl.h>
+
+#include "manager.h"
+
+void gnss_init(struct EG25Manager *manager, toml_table_t *config);
+void gnss_destroy(struct EG25Manager *manager);
+gboolean gnss_upload_assistance_data(struct EG25Manager *manager);
diff --git a/src/gpio.c b/src/gpio.c
index a5d3bf0..aae9b94 100644
--- a/src/gpio.c
+++ b/src/gpio.c
@@ -6,6 +6,8 @@
 
 #include "gpio.h"
 
+#include <unistd.h>
+
 #define GPIO_CHIP1_LABEL "1c20800.pinctrl"
 #define GPIO_CHIP2_LABEL "1f02c00.pinctrl"
 
@@ -52,7 +54,6 @@ int gpio_sequence_shutdown(struct EG25Manager *manager)
 int gpio_sequence_suspend(struct EG25Manager *manager)
 {
     gpiod_line_set_value(manager->gpio_out[GPIO_OUT_APREADY], 1);
-    gpiod_line_set_value(manager->gpio_out[GPIO_OUT_DTR], 1);
 
     g_message("Executed suspend sequence");
 
@@ -62,13 +63,32 @@ int gpio_sequence_suspend(struct EG25Manager *manager)
 int gpio_sequence_resume(struct EG25Manager *manager)
 {
     gpiod_line_set_value(manager->gpio_out[GPIO_OUT_APREADY], 0);
-    gpiod_line_set_value(manager->gpio_out[GPIO_OUT_DTR], 0);
 
     g_message("Executed resume sequence");
 
     return 0;
 }
 
+int gpio_sequence_wake(struct EG25Manager *manager)
+{
+    gpiod_line_set_value(manager->gpio_out[GPIO_OUT_DTR], 0);
+
+    /* Give the modem 200ms to wake from soft sleep */
+    usleep(200000);
+
+    g_message("Executed soft wake sequence");
+
+    return 0;
+}
+
+int gpio_sequence_sleep(struct EG25Manager *manager)
+{
+    gpiod_line_set_value(manager->gpio_out[GPIO_OUT_DTR], 1);
+    g_message("Executed soft sleep sequence");
+
+    return 0;
+}
+
 static guint get_config_gpio(toml_table_t *config, const char *id)
 {
     toml_datum_t value = toml_int_in(config, id);
diff --git a/src/gpio.h b/src/gpio.h
index 8d94013..a041bdc 100644
--- a/src/gpio.h
+++ b/src/gpio.h
@@ -15,5 +15,7 @@ int gpio_sequence_poweron(struct EG25Manager *state);
 int gpio_sequence_shutdown(struct EG25Manager *state);
 int gpio_sequence_suspend(struct EG25Manager *state);
 int gpio_sequence_resume(struct EG25Manager *state);
+int gpio_sequence_wake(struct EG25Manager *state);
+int gpio_sequence_sleep(struct EG25Manager *state);
 
 gboolean gpio_check_poweroff(struct EG25Manager *manager, gboolean keep_down);
diff --git a/src/manager.c b/src/manager.c
index c0b8a43..d13a2a0 100644
--- a/src/manager.c
+++ b/src/manager.c
@@ -15,6 +15,7 @@
 #include "ofono-iface.h"
 #include "suspend.h"
 #include "udev.h"
+#include "gnss.h"
 
 #include <fcntl.h>
 #include <signal.h>
@@ -342,6 +343,7 @@ int main(int argc, char *argv[])
     ofono_iface_init(&manager);
     suspend_init(&manager, toml_table_in(toml_config, "suspend"));
     udev_init(&manager, toml_table_in(toml_config, "udev"));
+    gnss_init(&manager, toml_table_in(toml_config, "gnss"));
 
     g_idle_add(G_SOURCE_FUNC(modem_start), &manager);
 
diff --git a/src/manager.h b/src/manager.h
index 30028e6..3e097b3 100644
--- a/src/manager.h
+++ b/src/manager.h
@@ -16,6 +16,32 @@
 
 #include "toml.h"
 
+typedef enum {
+    EG25_GNSS_STEP_FIRST = 0,
+#ifdef HAVE_MMGLIB
+    EG25_GNSS_STEP_MM_GNSS_DISABLE,
+#endif
+    EG25_GNSS_STEP_AT_GNSS_DISABLE,
+    EG25_GNSS_STEP_FETCH_ASSISTANCE_DATA,
+    EG25_GNSS_STEP_INIT_UPLOAD,
+    EG25_GNSS_STEP_UPLOAD,
+    EG25_GNSS_STEP_FINISH_UPLOAD,
+#ifdef HAVE_MMGLIB
+    EG25_GNSS_STEP_MM_GNSS_ENABLE,
+#endif
+    EG25_GNSS_STEP_AT_QGPS_ENABLE,
+    EG25_GNSS_STEP_LAST,
+} EG25GNSSStep;
+
+typedef enum {
+    EG25_GNSS_SOURCE_NONE = 0,
+    EG25_GNSS_SOURCE_NMEA = 1 << 0,
+    EG25_GNSS_SOURCE_RAW = 1 << 1,
+    EG25_GNSS_SOURCE_UNMANAGED = 1 << 2,
+    EG25_GNSS_SOURCE_QGPS = 1 << 3,
+} EG25GNSSSource;
+
+
 enum EG25State {
     EG25_STATE_INIT = 0,
     EG25_STATE_POWERED, // Power-on sequence has been executed, but the modem isn't on yet
@@ -47,15 +73,24 @@ struct EG25Manager {
     int at_fd;
     guint at_source;
     GList *at_cmds;
+    void (*at_callback)(struct EG25Manager *manager, const char *response);
 
     enum EG25State modem_state;
     gchar *modem_usb_id;
 
+    gboolean gnss_assistance_enabled;
+    EG25GNSSSource gnss_sources;
+    EG25GNSSStep gnss_assistance_step;
+    gint gnss_assistance_fd;
+    gchar *gnss_assistance_url;
+    gchar *gnss_assistance_file;
+
     enum ModemIface modem_iface;
     guint mm_watch;
 #ifdef HAVE_MMGLIB
     MMManager *mm_manager;
     MMModem *mm_modem;
+    MMModemLocation *mm_location;
 #endif
     guint ofono_watch;
     GDBOManager *ofono_manager;
diff --git a/src/meson.build b/src/meson.build
index f9eb27f..69a7e7e 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -15,6 +15,8 @@ src = [
         'suspend.c', 'suspend.h',
         'toml.c', 'toml.h',
         'udev.c', 'udev.h',
+        'gnss.c', 'gnss.h',
+        gdbofono_headers,
 ]
 
 if mmglib_dep.found()
diff --git a/src/mm-iface.c b/src/mm-iface.c
index d6a74f8..577a718 100644
--- a/src/mm-iface.c
+++ b/src/mm-iface.c
@@ -32,7 +32,7 @@ static void add_modem(struct EG25Manager *manager, GDBusObject *object)
 
     g_assert(MM_IS_OBJECT (object));
     manager->mm_modem = mm_object_get_modem(MM_OBJECT(object));
-    g_assert(manager->mm_modem != NULL);
+    g_assert_nonnull(manager->mm_modem);
 
     if (manager->modem_state == EG25_STATE_RESUMING) {
         if (manager->modem_recovery_timer) {
@@ -60,6 +60,16 @@ static void add_modem(struct EG25Manager *manager, GDBusObject *object)
     g_signal_connect(gdbus_modem, "state-changed", G_CALLBACK(state_changed_cb), manager);
 }
 
+static void add_modem_location(struct EG25Manager *manager, GDBusObject *object)
+{
+    const gchar *path;
+
+    path = g_dbus_object_get_object_path(object);
+    g_message("Adding new modem with location capabilities `%s'", path);
+    manager->mm_location = mm_object_get_modem_location(MM_OBJECT(object));
+    g_assert_nonnull(manager->mm_location);
+}
+
 static void interface_added_cb (struct EG25Manager *manager,
                                 GDBusObject        *object,
                                 GDBusInterface     *interface)
@@ -72,6 +82,9 @@ static void interface_added_cb (struct EG25Manager *manager,
 
     if (g_strcmp0(info->name, MM_DBUS_INTERFACE_MODEM) == 0)
         add_modem(manager, object);
+
+    if (g_strcmp0(info->name, MM_DBUS_INTERFACE_MODEM_LOCATION) == 0)
+        add_modem_location(manager, object);
 }
 
 
@@ -183,6 +196,9 @@ static void mm_iface_clean(struct EG25Manager *manager)
         g_free(manager->modem_usb_id);
         manager->modem_usb_id = NULL;
     }
+    if (manager->modem_iface == MODEM_IFACE_MODEMMANAGER) {
+        manager->modem_iface = MODEM_IFACE_NONE;
+    }
 }
 
 static void mm_vanished_cb(GDBusConnection    *connection,
diff --git a/udev/80-modem-eg25.rules b/udev/80-modem-eg25.rules
index 5fb6970..c25179f 100644
--- a/udev/80-modem-eg25.rules
+++ b/udev/80-modem-eg25.rules
@@ -1,5 +1,4 @@
 ACTION=="add", SUBSYSTEM=="usb", DRIVERS=="usb", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{power/control}="auto"
 ACTION=="add", SUBSYSTEM=="usb", DRIVERS=="usb", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{power/autosuspend_delay_ms}="3000"
 ACTION=="add", SUBSYSTEM=="usb", DRIVERS=="usb", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{power/wakeup}="enabled"
-ACTION=="add", SUBSYSTEM=="usb", DRIVERS=="usb", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{avoid_reset_quirk}="1"
 ACTION=="add", SUBSYSTEM=="usb", DRIVERS=="usb", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ATTR{power/persist}="0"