Chinese translation of Hitler no Fukatsu, MMC1 but larger than 256k

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dink
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Chinese translation of Hitler no Fukatsu, MMC1 but larger than 256k

Post by dink » Fri Jun 19, 2020 6:42 am

I have found a bit of a curiosity. A few days back, a buddy of mine asked if I could get the Chinese translation of Hitler no Fukatsu (Bionic Commando) to work in my emulator. At this point, it only boots in VirtuaNES - not working in Mesen and FCEUX.
Files in GoodNES:
Hitler no Fukkatsu - Top Secret (J) [T+Chi].nes
Hitler no Fukkatsu - Top Secret (J) [T+Chi][a1].nes

It's MMC1, but the romsize is 0x48000 (294912) bytes
There is data at 0x40000 - 48000. It boots in VirtuaNES because VirtuaNES maps the last bank of the rom (-1) to c000-ffff
(iirc FCEUX/MESEN maps bank 0xf to c000-ffff)

The part that I wonder about the most: how is the game going to access PRG @ 0x40000 - 0x43fff? The fifth bit is usually masked out on roms under 512k w/MMC1.

Do you think the creators of this translation relied on bugs in old emulators, or did this come from a cart dump, or ?? Ideas? :)

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Quietust
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Re: Chinese translation of Hitler no Fukatsu, MMC1 but larger than 256k

Post by Quietust » Fri Jun 19, 2020 10:30 am

dink wrote:
Fri Jun 19, 2020 6:42 am
The part that I wonder about the most: how is the game going to access PRG @ 0x40000 - 0x43fff? The fifth bit is usually masked out on roms under 512k w/MMC1.
I'm guessing that it expects all of PRG 40000-47FFF to be mapped to CPU $8000-$FFFF if the MMC1 resets in 32KB bank mode.
dink wrote:
Fri Jun 19, 2020 6:42 am
Do you think the creators of this translation relied on bugs in old emulators, or did this come from a cart dump, or ?? Ideas? :)
I can all but guarantee that it's the former - most early ROM hacks and translations were only designed to work in the most popular emulators available at the time, and as a result many of them don't work on actual hardware (or in more accurate emulators).
Quietust, QMT Productions
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Dwedit
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Re: Chinese translation of Hitler no Fukatsu, MMC1 but larger than 256k

Post by Dwedit » Fri Jun 19, 2020 7:51 pm

Oh gosh, if this expects a 256 + 32K game to use the bankswitching rules of usual 256K MMC1, but with last page stuck in the second 512K, there's no way this would ever work, it would need to be redone. Real 512K cartridges use CHR ROM selection bit to determine which 256K page to select, so you can't mix the two banks.
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