Skunkboard and booting unencrypted cds?

[Starcat]

I tried to load a binary for cartspace $802000 that should boot unencrypted cds. The upload itself seemed fine.

But one thing I can not yet figure out is, how do I boot the cart instead of the CD unit?

 

Is this whole idea of using the skunkboard to run unencrypted cds possible?

[kskunk]

I tried to load a binary for cartspace $802000 that should boot unencrypted cds. The upload itself seemed fine.

But one thing I can not yet figure out is, how do I boot the cart instead of the CD unit?

 

Is this whole idea of using the skunkboard to run unencrypted cds possible?

 

It's tricky. The Skunkboard doesn't allow the CD boot ROM to run unless you press the C button. So just loading a bypass cart image to the Skunkboard and running it without pressing the C button doesn't work.

 

However, you could try loading the bypass cart image (don't use the second bank), then reset the Jaguar while holding the C button. What should happen is that the Skunkboard will see you pressing C, then pass control to the CD boot ROM, which may in turn inspect the cart, see the bypass image, and pass control back to the bypass image to do its thing.

 

I haven't tried this so there are probably pitfalls. Maybe this gives you some ideas though.

 

Another approach is to accept that the Skunkboard is going to get control first, and put some code into your image to boot the CD boot ROM and then return control back to the Skunkboard. Now that everybody has the CD boot ROM listing this shouldn't be that hard.

 

If the above hints don't make it work, you could also try altering your bypass image to manually copy the CD BIOS into low memory (under $4000) before attempting to boot the CD. Some Alpine-based CD test tools do that because the Alpine hijacks CD control just like the Skunkboard does.

 

- KS

Edited June 11, 2009 by kskunk