diff --git a/src/mame/drivers/saitek_schess.cpp b/src/mame/drivers/saitek_schess.cpp
index fd026a0e72d..66b3e5896a5 100644
--- a/src/mame/drivers/saitek_schess.cpp
+++ b/src/mame/drivers/saitek_schess.cpp
@@ -157,7 +157,6 @@ READ8_MEMBER(schess_state::input_r)
 
 void schess_state::main_map(address_map &map)
 {
-	map.unmap_value_high();
 	map(0x0000, 0x03ff).ram();
 	map(0x4000, 0x4000).w(FUNC(schess_state::leds1_w));
 	map(0x4800, 0x4800).w(FUNC(schess_state::control_w));
@@ -180,7 +179,7 @@ static INPUT_PORTS_START( schess )
 	PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_T) PORT_NAME("Take Back")
 	PORT_BIT(0x10, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_L) PORT_NAME("Level")
 	PORT_BIT(0x20, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_W) PORT_NAME("White")
-	PORT_BIT(0x40, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_4) PORT_CODE(KEYCODE_5_PAD) PORT_NAME("Knight")
+	PORT_BIT(0x40, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_4) PORT_CODE(KEYCODE_4_PAD) PORT_NAME("Knight")
 	PORT_BIT(0x80, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_1) PORT_CODE(KEYCODE_1_PAD) PORT_NAME("King")
 
 	PORT_START("IN.1")
@@ -200,7 +199,7 @@ static INPUT_PORTS_START( schess )
 	PORT_BIT(0x10, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_M) PORT_NAME("Move")
 	PORT_BIT(0x20, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_V) PORT_NAME("Verify / Set Up")
 	PORT_BIT(0x40, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_6) PORT_CODE(KEYCODE_6_PAD) PORT_NAME("Pawn")
-	PORT_BIT(0x80, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_5) PORT_CODE(KEYCODE_4_PAD) PORT_NAME("Bishop")
+	PORT_BIT(0x80, IP_ACTIVE_HIGH, IPT_KEYPAD) PORT_CODE(KEYCODE_5) PORT_CODE(KEYCODE_5_PAD) PORT_NAME("Bishop")
 INPUT_PORTS_END