diff --git a/src/mame/drivers/megadrvb.c b/src/mame/drivers/megadrvb.c
index d3525f29ee8..d1814020e6f 100644
--- a/src/mame/drivers/megadrvb.c
+++ b/src/mame/drivers/megadrvb.c
@@ -738,27 +738,14 @@ DRIVER_INIT_MEMBER(md_boot_state,srmdb)
 {
 	UINT8* rom = machine().root_device().memregion("maincpu")->base();
 
-	/* todo, reduce bitswaps to single swap */
 	for (int x = 0x00001; x < 0x40000; x += 2)
 	{
-		rom[x] = rom[x] ^ 0xff;
-		rom[x] = BITSWAP8(rom[x], 7,6,5,4,3,2,1,0);
-		rom[x] = BITSWAP8(rom[x], 1,6,5,4,3,2,7,0);
-		rom[x] = BITSWAP8(rom[x], 7,6,5,3,4,2,1,0);
-		rom[x] = BITSWAP8(rom[x], 7,6,5,2,3,4,1,0);
-		rom[x] = BITSWAP8(rom[x], 5,6,7,4,3,2,1,0);
-		rom[x] = BITSWAP8(rom[x], 7,5,6,4,3,2,1,0);
+		rom[x] = BITSWAP8(rom[x] ^ 0xff, 5,1,6,2,4,3,7,0);
 	}
 
 	for (int x = 0x40001; x < 0x80000; x += 2)
 	{
-		rom[x] = BITSWAP8(rom[x], 7,6,5,4,3,2,1,0);
-		rom[x] = BITSWAP8(rom[x], 7,6,1,4,3,2,5,0);
-		rom[x] = BITSWAP8(rom[x], 7,6,5,4,0,2,1,3);
-		rom[x] = BITSWAP8(rom[x], 2,6,5,4,3,7,1,0);
-		rom[x] = BITSWAP8(rom[x], 7,6,5,0,3,2,1,4);
-		rom[x] = BITSWAP8(rom[x], 7,6,5,1,3,2,4,0);
-
+		rom[x] = BITSWAP8(rom[x] ^ 0x00, 2,6,1,5,0,7,3,4);
 	}
 
 	// boot vectors don't seem to be valid, so they are patched...
diff --git a/src/mame/machine/pgmprot1.c b/src/mame/machine/pgmprot1.c
index 3539d37447f..18b78b05748 100644
--- a/src/mame/machine/pgmprot1.c
+++ b/src/mame/machine/pgmprot1.c
@@ -952,8 +952,11 @@ void command_handler_kov(pgm_arm_type1_state *state, int pc)
 		break;
 
 		case 0xcc: // Background layer offset
-			if (state->m_value0 & 0x400) state->m_value0 = -(0x400 - (state->m_value0 & 0x3ff));
-			state->m_valueresponse = 0x900000 + ((state->m_kov_cb_value + (state->m_value0 * 0x40)) * 4);
+		{
+			int y = state->m_value0;
+			if (y & 0x400) y = -(0x400 - (y & 0x3ff));
+			state->m_valueresponse = 0x900000 + ((state->m_kov_cb_value + (y * 0x40)) * 4);
+		}
 		break;
 
 		case 0xd0: // Text palette offset
@@ -1015,7 +1018,7 @@ void command_handler_kov(pgm_arm_type1_state *state, int pc)
 
 		default:
 			state->m_valueresponse = 0x880000;
-//          bprintf (PRINT_NORMAL, _T("Unknown ASIC27 command: %2.2x data: %4.4x\n"), (data ^ state->m_valuekey) & 0xff, state->m_value0);
+//          		logerror("Unknown ASIC27 command: %2.2x data: %4.4x\n", (data ^ state->m_valuekey) & 0xff, state->m_value0);
 		break;
 	}
 }