diff --git a/src/mame/drivers/apple2gs.cpp b/src/mame/drivers/apple2gs.cpp
index 083b2b77d80..86cd4da5be5 100644
--- a/src/mame/drivers/apple2gs.cpp
+++ b/src/mame/drivers/apple2gs.cpp
@@ -2051,7 +2051,7 @@ READ8_MEMBER(apple2gs_state::c000_r)
 	}
 
 	slow_cycle();
-	u8 uFloatingBus7 = read_floatingbus();
+	u8 uFloatingBus7 = read_floatingbus() & 0x7f;
 
 	switch (offset)
 	{