I accidentally made a pretty funny SYSCARD3.0 bios discovery Jul 24, 2020 3:09:06 GMT
Post by mafoo343 on Jul 24, 2020 3:09:06 GMT
Recently, I purchased a copy of the Ginga Ojousama Densetsu Collection for the PSP which is a compilation of various PC Engine games. After the game arrived, I immediately backed the game up using custom firmware on my PSP so that I could emulate the title in PPSSPP. I was curious to see how much the devs changed up the game files when porting the three titles in the collection, so I opened up the game's ISO and began browsing around. Inside, I found a folder called "CDROM" and in it were three separate folders for each game and a file called "SYSCARD3P.PCE". As it turns out, it seems like the developers kept each of the games more or less intact compared to their PC Engine original counterparts. Even more strange was the fact that the game pretty much has a SYSCARD3.0 bios just sitting around in the file directory. This made me curious as to whether or not this version of the SYSCARD3.0 bios could work in an actual PC Engine emulator. At first I tried "Turbo Engine" with a physical copy of Galaxy Fraulein Yuna 2 and the game booted into an error message saying something along the lines of "The backup memory isn't initialized, please initialize the backup memory and restart." I was curious to see if I could get any further with another emulator, so I renamed the bios "SYSCARD3.PCE" and tried using "Beetle PCE" in Retroarch instead. Oddly enough, the game actually booted up and was fully playable, audio and all.
In all honesty, I'm kind of baffled at this point, because on all accounts, that should never have worked. From what I can tell the bios was tweaked and modified, making it about 100kb larger than the traditional SYSCARD3.0 bios based on the checksums I've seen. Furthermore, it seems to struggle to get anywhere on pretty much any other PC Engine emulator I've tested. But for some odd reason, the PSP PC Engine bios in conjunction with Retroarch seems to work just fine. Not that I'm complaining or anything, this discovery is something I find to be really cool.
With that being said though, I'm a little curious, does anyone have any idea why on Earth this actually works for this emulator in particular but not the others? Because in all honesty, I'm astonished this actually managed to work at all.
Edit: For anyone that's interested, here's a picture of the cute error I got while trying to use the PSP SYSCARD bios with Turbo Engine to play Galaxy Fraulein Yuna 2.