diff --git a/data/devices/logitech-g502-x-plus.device b/data/devices/logitech-g502-x-plus.device
new file mode 100644
index 00000000..4fb153b6
--- /dev/null
+++ b/data/devices/logitech-g502-x-plus.device
@@ -0,0 +1,8 @@
+[Device]
+Name=Logitech G502 X PLUS
+DeviceMatch=usb:046d:c095
+DeviceType=mouse
+Driver=hidpp20
+
+[Driver/hidpp20]
+Quirk=G502X_PLUS
diff --git a/src/driver-hidpp20.c b/src/driver-hidpp20.c
index 7c4cfb00..4a9b4c67 100644
--- a/src/driver-hidpp20.c
+++ b/src/driver-hidpp20.c
@@ -411,7 +411,13 @@ hidpp20drv_read_led_8071(struct ratbag_led *led, struct hidpp20drv_data* drv_dat
 	hidpp20_rgb_effects_get_device_info(drv_data->dev, &device_info);
 	cluster_info = drv_data->led_infos.color_leds_8071[led->index];
 	profile = &drv_data->profiles->profiles[led->profile->index];
-	h_led = &profile->leds[led->index];
+	if (drv_data->dev->quirk == HIDPP20_QUIRK_G502X_PLUS) {
+		// On G502X+ the second slot controls the user configurable LED.
+		// (Note: There is only 1 reported LED, it just happens to use 2nd index though)
+		h_led = &profile->leds[1];
+	} else {
+		h_led = &profile->leds[led->index];
+	}
 
 	switch (h_led->mode) {
 	case HIDPP20_LED_ON:
@@ -689,7 +695,13 @@ hidpp20drv_update_led_8070_8071(struct ratbag_led *led, struct ratbag_profile* p
 
 	if (drv_data->capabilities & HIDPP_CAP_ONBOARD_PROFILES_8100) {
 		h_profile = &drv_data->profiles->profiles[profile->index];
-		h_led = &(h_profile->leds[led->index]);
+		if (drv_data->dev->quirk == HIDPP20_QUIRK_G502X_PLUS) {
+			// On G502X+ the second slot controls the user configurable LED.
+			// (Note: There is only 1 reported LED, it just happens to use 2nd index though)
+			h_led = &(h_profile->leds[1]);
+		} else {
+			h_led = &(h_profile->leds[led->index]);
+		}
 	}
 
 	if (!h_led)
diff --git a/src/hidpp20.c b/src/hidpp20.c
index 83531c0f..221234be 100644
--- a/src/hidpp20.c
+++ b/src/hidpp20.c
@@ -110,6 +110,7 @@ hidpp20_get_quirk_string(enum hidpp20_quirk quirk)
 	CASE_RETURN_STRING(HIDPP20_QUIRK_NONE);
 	CASE_RETURN_STRING(HIDPP20_QUIRK_G305);
 	CASE_RETURN_STRING(HIDPP20_QUIRK_G602);
+	CASE_RETURN_STRING(HIDPP20_QUIRK_G502X_PLUS);
 	}
 
 	abort();
@@ -1802,6 +1803,7 @@ int hidpp20_adjustable_report_rate_set_report_rate(struct hidpp20_device *device
 #define HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G303	0x02
 #define HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G900	0x03
 #define HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G915	0x04
+#define HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G502X	0x05
 #define HIDPP20_ONBOARD_PROFILES_MACRO_TYPE_G402	0x01
 
 #define HIDPP20_USER_PROFILES_G402			0x0000
@@ -1831,7 +1833,8 @@ union hidpp20_internal_profile {
 		} name;
 		struct hidpp20_internal_led leds[2]; /* G303, g502, g900 only */
 		struct hidpp20_internal_led alt_leds[2];
-		uint8_t free[2];
+		uint8_t custom_animation_index; // G502X Plus, G705
+		uint8_t free; // unused
 		uint16_t crc;
 	} __attribute__((packed)) profile;
 };
@@ -2220,7 +2223,8 @@ hidpp20_onboard_profiles_validate(struct hidpp20_device *device,
 	if ((info->profile_format_id != HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G402) &&
 	    (info->profile_format_id != HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G303) &&
 	    (info->profile_format_id != HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G900) &&
-	    (info->profile_format_id != HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G915)) {
+	    (info->profile_format_id != HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G915) &&
+	    (info->profile_format_id != HIDPP20_ONBOARD_PROFILES_PROFILE_TYPE_G502X)) {
 		hidpp_log_error(&device->base,
 				"Profile layout not supported: 0x%02x.\n",
 				info->profile_format_id);
@@ -2959,6 +2963,18 @@ hidpp20_onboard_profiles_write_profile(struct hidpp20_device *device,
 
 	memcpy(pdata->profile.name.txt, profile->name, sizeof(profile->name));
 
+	// Mice like G502X can store custom animations onboard.
+	// ratbag does not support this, so we set it to disable it to ensure
+	// that the actual lighting matches the user's settings.
+	if (device->quirk == HIDPP20_QUIRK_G502X_PLUS)
+	{
+		// Note(sewer56): There are two known mice which use this field;
+		// G502X PLUS and G705. [And I only own one of these.] But it's not known how 
+		// prevalent this is elsewhere, so in the interest of defensive programming;
+		// we're not setting this on unknown mice. 
+		pdata->profile.custom_animation_index = 0x00;
+	}
+
 	rc = hidpp20_onboard_profiles_write_sector(device, sector, sector_size, data, true);
 	if (rc < 0) {
 		hidpp_log_error(&device->base, "failed to write profile\n");
diff --git a/src/hidpp20.h b/src/hidpp20.h
index cddf3866..7e14f359 100644
--- a/src/hidpp20.h
+++ b/src/hidpp20.h
@@ -55,6 +55,7 @@ enum hidpp20_quirk {
 	HIDPP20_QUIRK_NONE,
 	HIDPP20_QUIRK_G305,
 	HIDPP20_QUIRK_G602,
+	HIDPP20_QUIRK_G502X_PLUS, // G502X+ uses 2nd LED slot instead of 1st.
 };
 
 struct hidpp20_device {
diff --git a/src/libratbag-data.c b/src/libratbag-data.c
index 0eb43c86..cd0f53ed 100644
--- a/src/libratbag-data.c
+++ b/src/libratbag-data.c
@@ -225,6 +225,8 @@ init_data_hidpp20(struct ratbag *ratbag,
 			data->hidpp20.quirk = HIDPP20_QUIRK_G305;
 		else if(streq(str, "G602"))
 			data->hidpp20.quirk = HIDPP20_QUIRK_G602;
+		else if(streq(str, "G502X_PLUS"))
+			data->hidpp20.quirk = HIDPP20_QUIRK_G502X_PLUS;
 	}
 }