diff --git a/src/boards/380.c b/src/boards/380.c
index f14ac63..2b53fb1 100644
--- a/src/boards/380.c
+++ b/src/boards/380.c
@@ -57,7 +57,7 @@ static void Sync(void)
 static DECLFR(M380Read)
 {
    if (latche & 0x100 && !isKN35A)
-      return CartBR(A | dipswitch);
+      return CartBR(A &~0x0F | dipswitch);
    return CartBR(A);
 }