@Darksoft Hey buddy, I found this topic right at the top of the forum list so I'm just going to use it instead of making a second thread. To catch everyone up, I got an ST-V mobo which works, passes all the tests including slave SH-2, verified with an authentic cart. When I use the old ST-V multicart (not the dark knight variant), with a smoke monster roll up pack, I can see the game is flashed correctly onto the cart. When booting up the ST-V, I get the screen announcing the correct game (i.e. if it's astra super stars, it'll say Astra Super Stars, if it's die hard arcade, it'll say die hard arcade, etc). After that, I get to the "checking system" screen and then I get black screen, nothing more.
I DM'd darksoft prior asking if perhaps the problem was a firmware issue, as I saw a post from 2018 where Darksoft mentioned a few multi-carts had shipped with the bootstrap loaded but not the firmware, but I'd have to buy a programmer to flash the firmware. However I bought the ST-V multicart in 2021 and I saw another post where they had indicated the lack of firmware problem had long been solved, so I'm thinking perhaps it's not a firmware problem. Darksoft suggested perhaps I have an incompatible bios, and I'm fairly certain this ST-V is a japanese unit but can't tell for sure. Reading this topic, it seems flashing an eeprom with the multibios is the way to go, and I have an eeprom programmer I can use. Darksoft asked me to take the topic to the boards instead of DM, hence this post.
What I need help with:
1) How can I identify what bios I have? The label text on my chip on my ST-V has deteriorated away to the point where it's a blurry mess that I can't really read well.
2) Anybody know where to find a 27C400 eeprom? Looking online they are hard to get and are going for something like $70?? That can't be right, can it?
3) Any other troubleshooting help would be appreciated.
EDIT: Alternatively, if anybody has an already programmed 27C400 they'd be willing to sell, I'd be up for buying it straight from them, that would save me a day of digging out the eeprom programmer haha.