Author Topic: Sega CD BIOS file on cartridge problem  (Read 3371 times)

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Offline MaarioS

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Sega CD BIOS file on cartridge problem
« on: November 13, 2015, 01:00 AM »
This isn't quite exactly the issue about the Everdrive but rather the overall idea about Sega CD BIOS loading. I tried to write the multiregion BIOS file to my regular EPROM cart and it always freezes on the main screen. Tried it several times and the result is always the same. Shouldn't the cartridge be somehow configured in order to make it work?? How does the Everdrive achieve this??

My setup is Sega Genesis model 2 (NTSC-US) + Sega CD model 2 (NTSC-US) and I try to write the multiregion BIOS file for model 2 USA version with swapbyte. Many thanks for any advices!!

Offline goombakid

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Re: Sega CD BIOS file on cartridge problem
« Reply #1 on: November 13, 2015, 06:16 AM »
Try using the non-byte swapped version.

Offline MaarioS

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Re: Sega CD BIOS file on cartridge problem
« Reply #2 on: November 13, 2015, 02:12 PM »
Try using the non-byte swapped version.

This will never work because Sega processor is built to read little-endian words only, meaning ALL cartridge memories have to be swapbyted, otherwise it will never work. The solution to that must be different

Offline goombakid

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Re: Sega CD BIOS file on cartridge problem
« Reply #3 on: November 13, 2015, 07:16 PM »
Sorry, was thinking of something else (or wasn't thinking at all, I've been sick).

Did you get your BIOS files from here?

https://www.dropbox.com/sh/fdt8185a8kpjozb/AABTFlxEOC323RcWQBf9j9wVa/everdrive-md/v2/free-bios?dl=0

I haven't used my EDMD for BIOS loading for a while now since I swapped out the Sega CD BIOS' with a region free one.