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Skunk & Boot ROM


swapd0

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I'm trying to copy the roar sample from the boot rom to ram and play it with u235se, but I get a weird sound. Maybe I can't access the Boot ROM because I got a Skunkboard inserted?

 

The sample (11025Hz) is located at Boot ROM offset 0xc1b4 to 0x127f4.

 

Edited by swapd0
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The boot ROM is 8-bit wide with 10 cycles access time. The Skunboard Flash memory is 16-bit wide with 5 cycles access time.

 

The settings in MEMCON1 affect both, so if you want to read the boot ROM, you need to change the value of this register (from code running in RAM, of course, otherwise it'll crash) and restore it after you're done.

 

Keep in mind that accessing the boot ROM will make your game incompatible with the BJL ROM.

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Ok, now I read the data properly but it looks that there are sightly differences in the Boot ROM, because I get some glitches at the start, but if I cut the jagbios.rom from 0xc1b4 to 0x127f4 and play it in Audacity it works...

 

Also I've dumped the values that I'm reading and they are part of the bitmap that is located before the sample.

Edited by swapd0
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  • 4 weeks later...

As far as I can remember there is only 2 BIOS version. One for M models and one for K models.
I seem to remember that one of these versions can work on the K and M models, while the other version can only work on one model.
It seems to me that the subject had already been approached, maybe in another forum, maybe by myself... And the difference between the 2 BIOS was the initialization startup, of the video I believe.

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