diff --git a/src/drivers/sdl/input.cpp b/src/drivers/sdl/input.cpp
index 05f4f41b..8dbd6f9a 100644
--- a/src/drivers/sdl/input.cpp
+++ b/src/drivers/sdl/input.cpp
@@ -134,6 +134,9 @@ static uint8 keyonce[MKK_COUNT];
 static int
 _keyonly(int a)
 {
+	// check for valid key
+	if(a > 350 || a < 0)
+		return(0);
     if(g_keyState[a]) {
         if(!keyonce[a]) {
             keyonce[a] = 1;