diff --git a/src/mame/drivers/at.cpp b/src/mame/drivers/at.cpp
index 1fd01202b45..18ef2ee0e7a 100644
--- a/src/mame/drivers/at.cpp
+++ b/src/mame/drivers/at.cpp
@@ -1858,7 +1858,6 @@ ROM_START( pccm209 )
 	ROM_CONTINUE( 0x10001, 0x08000 )
 ROM_END
 
-
 // ID: unknown - ASI 100B0, identified as “HAM 12 TI 286 Motherboard ZERO WAIT” - Chipset: Texas Instruments TACT82301PB, TACT82302PB, TACT82303PB (cf. at386sx)
 // CPU: xxx, FPU: IIT 2C87-12 - RAM: 1MB in DIP, 4xSIPP30 - OSC: 24.000MHz, 14.31818 - ISA8: 3, ISA16: 5
 ROM_START( asi100b0 ) // BIOS-String: D286-1112-040990-K0
@@ -1913,7 +1912,13 @@ ROM_END
 // BIOS-String: S286-6181-101590-K0
 ROM_START( pccm205 )
 	ROM_REGION16_LE(0x20000, "bios", 0)
-	ROM_LOAD16_BYTE( "m205.bin", 0x10000, 0x8000, CRC(6f7bc8d6) SHA1(14062505b316e0d4409fb4e502651e09fea0a4c1) )
+	// 0: v2.25, 17 January, 1991 (C) 1990 PC Chips INC.
+	ROM_SYSTEM_BIOS(0, "v225", "PC Chips v2.25")
+	ROMX_LOAD( "m205.bin", 0x10000, 0x8000, CRC(6f7bc8d6) SHA1(14062505b316e0d4409fb4e502651e09fea0a4c1), ROM_SKIP(1) | ROM_BIOS(0) )
+	ROM_CONTINUE( 0x10001, 0x8000)
+	// 1: v2.23, 29 December, 1990 (C) 1990 EVER-SUCCESS SYSTEMS LTD.
+	ROM_SYSTEM_BIOS(1, "v223", "Ever-Success Systems v2.23")
+	ROMX_LOAD( "m205_odd.bin", 0x10000, 0x8000, CRC(3a8ed558) SHA1(0648a2f1674bb07a175b983f107bb72c38ac1e61), ROM_SKIP(1) | ROM_BIOS(1) )
 	ROM_CONTINUE( 0x10001, 0x8000)
 ROM_END