diff --git a/src/gba/sio.h b/src/gba/sio.h
index 7110ff7bf..5d6d9f39d 100644
--- a/src/gba/sio.h
+++ b/src/gba/sio.h
@@ -42,9 +42,9 @@ struct GBASIO {
 			unsigned internalSc : 1;
 			unsigned si : 1;
 			unsigned idleSo : 1;
-			unsigned : 4;
-			unsigned start : 1;
 			unsigned : 3;
+			unsigned start : 1;
+			unsigned : 4;
 			unsigned length : 1;
 			unsigned : 1;
 			unsigned irq : 1;