Please Help Again re Weak Bits

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plaxamate
Posts: 10
Joined: Sat Aug 29, 2020 11:07 pm

Please Help Again re Weak Bits

Post by plaxamate »

I have an original dump of the NTSC copy of Indiana Jones and the Temple of Doom for Commodore 64. It appears, according to c64preservation.com, that it has a "weak bits" protection. According to viewtopic.php?f=10&t=1231, I should be able to hex edit the G64 to fix it for emulators, but I cannot figure out how to do this. In watching the Monitor in VICE, it looks like it's on Track 1, but beyond that I cannot tell what to edit. I've placed the dump and G64 at https://www.dropbox.com/sh/ymgsqx01xgo7 ... c7Wia?dl=0. Thank you for any help you can render.

Plaxamate
ZrX
Posts: 641
Joined: Tue Dec 06, 2011 9:09 pm

Re: Please Help Again re Weak Bits

Post by ZrX »

If you open the G64 file in a hexeditor and go to offset 0x1116 you should see bytes D5 AA 33 86 30 AA D4, and you only need to replace the 33 86 30 with 00 00 00.

Few consecutive 00-bytes in a G64 is a way to tell emulators that this part of the track should generate random data when read. DTC also knows this, but only for the most used protection types and the Mindscape version unfortunately isn't implemented.
plaxamate
Posts: 10
Joined: Sat Aug 29, 2020 11:07 pm

Re: Please Help Again re Weak Bits

Post by plaxamate »

This worked perfectly, thank you! I'll know how to fix this in the future now.
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