diff --git a/CHANGES b/CHANGES
index 293bb58a1..d79cb4f4c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,7 @@ Emulation fixes:
  - GBA GPIO: Fix gyro read-out start (fixes mgba.io/i/3141)
  - GBA SIO: Fix MULTI mode SIOCNT bit 7 writes on secondary GBAs (fixes mgba.io/i/3110)
 Other fixes:
+ - Qt: Fix crash when applying changes to GB I/O registers in I/O view
  - Updater: Fix updating appimage across filesystems
 Misc:
  - Vita: Add imc0 and xmc0 mount point support
diff --git a/src/platform/qt/IOViewer.cpp b/src/platform/qt/IOViewer.cpp
index 46c0d8dbb..b0c387914 100644
--- a/src/platform/qt/IOViewer.cpp
+++ b/src/platform/qt/IOViewer.cpp
@@ -1689,7 +1689,20 @@ void IOViewer::bitFlipped() {
 void IOViewer::writeback() {
 	{
 		CoreController::Interrupter interrupter(m_controller);
-		GBAIOWrite(static_cast<GBA*>(m_controller->thread()->core->board), m_register, m_value);
+		switch (m_controller->platform()) {
+#ifdef M_CORE_GB
+		case mPLATFORM_GB:
+			GBIOWrite(static_cast<GB*>(m_controller->thread()->core->board), m_register, m_value);
+			break;
+#endif
+#ifdef M_CORE_GBA
+		case mPLATFORM_GBA:
+			GBAIOWrite(static_cast<GBA*>(m_controller->thread()->core->board), m_register, m_value);
+			break;
+#endif
+		case mPLATFORM_NONE:
+			return;
+		}
 	}
 	updateRegister();
 }