Astebros garbled graphics/crashing

[joepogo]

Hi eke, hope all is well with you.

Recently a homebrew game called Astebros (of a prequel to demons of asteborg) was released in it's full version and this game exhibits many issues on GPGX.

Tested on my Wii and latest retroarch.

Once you load up the game the language options screen is immediately garbled and once in game when get to the map the map becomes garbled and then black screen crashes.

The two demos work fine but the new full release does some weird bank switching as stated by the devs.

This probably hasn't been reported yet due to the full release just coming out.

Anyways, just putting it up here for you and thanks again for all you do!

https://www.kickstarter.com/projects/neofid-studios/astebros

[ekeeke]

Where does the ROM comes from ? I think the STEAM version of their games has its header modified so it could work with the emulator they are using (Blastem I think) but because they are using a field value reserved to indicate Everdrive extended ROM mapper, it does not work on Everdrive flashcarts (or emulators like this one which emulates Everdtive extended ROM mapper).

Open the ROM header in an hex editor and sees if it has "SEGA SSF" or something like that. If that's the case, changing this to "SEGA GENESIS" or "SEGA MEGADRIVE" (or "SEGA DOA" as in original Demons of Asteborg cartridge) should fix it.

[joepogo]

Hey Eke,

Thanks so much for the response. Just took a peek at the header in a hex editor and it says:

SEGA DOA (C) SDGK 2023 NEOFID STUDIOS 2 023

No sign of SSF anywhere that i can see. :)

[ekeeke]

OK. What is the size of the ROM file ? Wii version has a maximal ROM size limited to 15MB currently (which was the size of their previous game) so if that game is larger, it will fail on Wii (but should work on Windows through Retroarch where the limit is 32MB).

[joepogo]

The rom file is around 6mb zipped if I remember correctly. If you need to, I can message you with what you need.

Yea, it fails on retroarch PC GPGX and Wii.

[ekeeke]

That's not a size issue, then. Does it work in other emulators ? I doubt they are using a new undocumented mapper since they are officially distributing ROM files for use in emulators but you never know.

[joepogo]

No, unzipped is 14.7mb. But it fails on genesis plus gx retroarch so def is not a size issue.

I read on their project page that there is some things they are doing with bankswitching, so not sure if it is a programmer issue or emulator side issue.

I sent you an email with some more information. Let me know if you do not get it. I still had your email from old communication we had many years ago. :)

[ekeeke]

Found out some bug in SRAM bank-switching emulation for games that also uses ROM bank-switching (ROM banks were not preserved). This is now fixed by https://github.com/ekeeke/Genesis-Plus-GX/commit/4bb149ba0b798294fbfc51de31a97af08c018542

[joepogo]

Great work as always eke! Thank you for all that you do!

[infval]

Open the ROM header in an hex editor and sees if it has "SEGA SSF" or something like that. If that's the case, changing this to "SEGA GENESIS" or "SEGA MEGADRIVE" (or "SEGA DOA" as in original Demons of Asteborg cartridge) should fix it.

The updated rom from Steam has "SEGA SSF". Your advice is working.