diff --git a/include/mgba/gba/interface.h b/include/mgba/gba/interface.h
index 3a5412645..90f5e0697 100644
--- a/include/mgba/gba/interface.h
+++ b/include/mgba/gba/interface.h
@@ -28,6 +28,10 @@ struct GBAVideoRenderer;
 
 extern const int GBA_LUX_LEVELS[10];
 
+enum {
+	mPERIPH_GBA_LUMINANCE = 0x1000
+};
+
 struct GBALuminanceSource {
 	void (*sample)(struct GBALuminanceSource*);
 
diff --git a/src/feature/gui/gui-runner.c b/src/feature/gui/gui-runner.c
index c26cbe662..ad59ae893 100644
--- a/src/feature/gui/gui-runner.c
+++ b/src/feature/gui/gui-runner.c
@@ -298,7 +298,7 @@ void mGUIRun(struct mGUIRunner* runner, const char* path) {
 		return;
 	}
 	if (runner->core->platform(runner->core) == PLATFORM_GBA) {
-		((struct GBA*) runner->core->board)->luminanceSource = &runner->luminanceSource.d;
+		runner->core->setPeripheral(runner->core, mPERIPH_GBA_LUMINANCE, &runner->luminanceSource.d);
 	}
 	mLOG(GUI_RUNNER, DEBUG, "Loading config...");
 	mCoreLoadForeignConfig(runner->core, &runner->config);
diff --git a/src/gba/core.c b/src/gba/core.c
index 2d653deca..4f7963cea 100644
--- a/src/gba/core.c
+++ b/src/gba/core.c
@@ -414,6 +414,9 @@ static void _GBACoreSetPeripheral(struct mCore* core, int type, void* periph) {
 	case mPERIPH_RUMBLE:
 		gba->rumble = periph;
 		break;
+	case mPERIPH_GBA_LUMINANCE:
+		gba->luminanceSource = periph;
+		break;
 	default:
 		return;
 	}
diff --git a/src/platform/libretro/libretro.c b/src/platform/libretro/libretro.c
index e640a91f0..d19c5006f 100644
--- a/src/platform/libretro/libretro.c
+++ b/src/platform/libretro/libretro.c
@@ -409,8 +409,7 @@ bool retro_load_game(const struct retro_game_info* game) {
 
 #ifdef M_CORE_GBA
 	if (core->platform(core) == PLATFORM_GBA) {
-		struct GBA* gba = core->board;
-		gba->luminanceSource = &lux;
+		core->setPeripheral(core, mPERIPH_GBA_LUMINANCE, &lux);
 
 		const char* sysDir = 0;
 		if (core->opts.useBios && environCallback(RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY, &sysDir)) {
diff --git a/src/platform/qt/GameController.cpp b/src/platform/qt/GameController.cpp
index 7d8484b84..486c22d6e 100644
--- a/src/platform/qt/GameController.cpp
+++ b/src/platform/qt/GameController.cpp
@@ -99,7 +99,7 @@ GameController::GameController(QObject* parent)
 		switch (context->core->platform(context->core)) {
 #ifdef M_CORE_GBA
 		case PLATFORM_GBA:
-			gba->luminanceSource = &controller->m_lux;
+			context->core->setPeripheral(context->core, mPERIPH_GBA_LUMINANCE, &controller->m_lux);
 			gba->audio.psg.forceDisableCh[0] = !controller->m_audioChannels[0];
 			gba->audio.psg.forceDisableCh[1] = !controller->m_audioChannels[1];
 			gba->audio.psg.forceDisableCh[2] = !controller->m_audioChannels[2];