diff --git a/src/mame/yamaha/tg100.cpp b/src/mame/yamaha/tg100.cpp
index c9ac46b00e3..192dc77322e 100644
--- a/src/mame/yamaha/tg100.cpp
+++ b/src/mame/yamaha/tg100.cpp
@@ -59,6 +59,7 @@ private:
 void tg100_state::tg100_map(address_map &map)
 {
 	map(0x00000000, 0x0007ffff).ram(); /* gate array stuff */
+	map(0x00000000, 0x000000ff).rom().region("prgrom", 0x00000);
 	map(0x00080000, 0x0009ffff).rom().region("prgrom", 0x00000);
 }
 
@@ -90,7 +91,6 @@ ROM_START( tg100 )
 	ROM_LOAD( "xk731c0.ic4", 0x00000, 0x20000, CRC(8fb6139c) SHA1(483103a2ffc63a90a2086c597baa2b2745c3a1c2) )
 
 	ROM_REGION(0x4000, "maincpu", 0)
-	ROM_LOAD( "hd6435208a00p.bin", 0x0000, 0x4000, NO_DUMP )
 	ROM_COPY( "prgrom", 0x0000, 0x0000, 0x4000 )
 
 	ROM_REGION(0x200000, "ymw258", 0)