It was published on Decemin Japan, Octoin North America, and Apin Europe. This routine prints the dreaded region error screen and locks itself on a endless loop:Ġ0000736 23fc c000 0000 00c0 0004 MOVE #0xc0000000,A_00c00004Ġ0000740 23d9 00c0 0000 MOVE (A1)+,A_00c00000Ġ0000746 203c 4604 0003 MOVE #0x46040003,D0Ġ0000754 60fe BRA B_754 <- this instruction locks the system upĪfter this, the data with the text message "ERROR! THIS IS A PAL-COMPATIBLE MEGA-CD FOR EXCLUSIVE USE IN SOUTHEAST ASIA."Ĭauses the conditional "Branch if EQual" to never happen, the next instruction (RTS) is executed and the Mega-CD boots as if nothing had happened.įixed the checksum with a ROM repair tool, tested it on a emulator, byte swapped, burned on a 128BK 16 bit eprom (27C210) and was ready to go.The Sega CD, launched as the Mega-CD in many areas outside North America and Brazil, is a CD-ROM frill for the Sega Genesis created by Sega as a component of the 4th era of computer game console system. This routine checks the status of the region bit at 0x00A10001 and returns (RTS) if the region is *NOT* set to "Export":Ġ0000716 1039 00a1 0001 MOVE.B A_00a10001,D0
This is how I got that check defeated: (For Asian Mega-CD Bios ROM: EPR-14563H 12/28-1991 1.00) Still, it doesn't solve the problem of the Mega-CD itself having a Mega Drive console region check on it's own BIOS ROM. So what I do to make PAL and US games work on my asian Mega CD is manually paste the japanese security program at the correct offset (0x00200) of the first sector and pad the size difference with 68000 NOP instructions (4E 71). security program: 1412 bytes -> "PRODUCED BY OR UNDER LICENSE FROM SEGA ENTERPRISES, LTD" Japanese security program: 342 Bytes -> "PRODUCED BY OR UNDER LICENCE FROM KABUSHIKI KAISHA SEGA ENTERPRISES"Įuropean security program: 1390 bytes -> "PRODUCED BY OR UNDER LICENSE FROM SEGA ENTERPRISES, LTD" I found out that it *tries* to relocate the boot loader of the game and injects the proper "security program" for the target region.Īlso I found out that the three regions have respectively: Since 2004/2005 (I don't remember well) I've been buying US and EU games and re-burning them on CDRs.īecause I don't like Datel's CDX and other similar stuff occupying my Mega Drive cartridge slot, I started to research how actually the SCDCONV program works. While we're at it (Dreamcast region modchip thread) I took my old MEGA-CD out of storage and started to thinker with it.
0 kommentar(er)
