if (nBIOS < 3 || nBIOS == 9) // Hacks for Neo-Geo MVS BIOS
{
int ofst = 0;
if (nBIOS == 0) ofst = 0x0C24; // sp-j3.sp1 JP, MVS, ? slot, Ver. 6
// if (nBIOS == 0) ofst = 0x1C28; // vs-bios.rom JP, MVS, ? slot, Ver. 5
// if (nBIOS == 0) ofst = 0x1B00; // sp-j2.rom JP, MVS, ? slot, Ver. 5
// sp1.jipan.1024 JP, MVS, 4 slot, Ver. 3
if (nBIOS == 1) ofst = 0x1AD6; // usa_2slt.bin US, MVS, 2 slot, Ver. 5
// if (nBIOS == 2) ofst = 0x0B00; // asia-s3.rom AS, MVS, 1 slot, Ver. 6
// if (nBIOS == 2) ofst = 0x1AD6; // sp-e.sp1 AS, MVS, 6 slow, Ver. 5
if (nBIOS == 2) ofst = 0x1B00; // sp-s2.sp1 AS, MVS, 1 slot, Ver. 5
// sp-s.sp1 AS, MVS, 4 slot, Ver. 3
if (nBIOS == 9) ofst = 0x0C2A; // 236-bios.bin AS, MVS, ? slot, Ver T1 (irrmaze BIOS)
// Remove memory check
*((unsigned short*)(Neo68KBIOS + ofst + 0x010000)) = 0x4E71;
*((unsigned short*)(Neo68KBIOS + ofst + 0x010002)) = 0x4E71;
*((unsigned short*)(Neo68KBIOS + ofst + 0x010016)) = 0x4EF9;
*((unsigned short*)(Neo68KBIOS + ofst + 0x010018)) = 0x00C1;
*((unsigned short*)(Neo68KBIOS + ofst + 0x01001A)) = 0x006A + ofst;
// Patch Calendar errors
*((unsigned short*)(Neo68KBIOS + ofst + 0x010114)) = 0x4E71;
*((unsigned short*)(Neo68KBIOS + ofst + 0x010116)) = 0x4E71;
*((unsigned short*)(Neo68KBIOS + ofst + 0x01011C)) = 0x4E71;
*((unsigned short*)(Neo68KBIOS + ofst + 0x01011E)) = 0x4E71;
// Patch checksum test
*((unsigned short*)(Neo68KBIOS + ofst + 0x010162)) = 0x4E71;
*((unsigned short*)(Neo68KBIOS + ofst + 0x010164)) = 0x4E71;
}
Yup, 271-bios.bin is the same as sp-j3.sp1 (well, a few bytes diff.)