Possible to Re-flash a Yamaha SCSI CDROM to fake an Apple CDROM ?

Swift Griggs swiftgriggs at gmail.com
Wed Jun 15 15:45:15 CDT 2016

On Wed, 15 Jun 2016, ethan at 757.org wrote:
> I'm not sure if it has anything to do with it, but over on the early SGI 
> and Sun and NeXT stuff you had to change the block size on the CD-ROM to 
> get them to work.

Yeah, I think you mean the 2048 vs 512 byte block size. SGI's use a 512 
byte size, IIRC. Folks were just talking about that a few weeks back, in 

> The early Toshiba drives had solder pads that could be split open or 
> re-closed to change block sizes and such to get them to work on all of 
> the different hardware types.

Most SCSI-based Yamaha and Pioneer drives have a jumper you can set for 
it. However, I tried this with my Pioneer SCSI CDROM and it still didn't 
work. I guess if nobody knows I can figure out how to run a 
debugger/syscall-profiler of some kind on MacOS 8.1 and fire up Disk Setup 
and see what it's actually looking for. My guess is it's just checking to 
make sure the SCSI vendor ID is "Apple" and then happily goes on with it's 
job. However, I just don't know for sure yet. 

I also don't know if altering a ROM image like that would have disastrous 
effects if, for example, the ROM image is appended with a CRC32 checksum 
that will fail once I flash it with a hacked image. I also am not sure if 
I can find the right spot in the firmware image to do the byte-patch. Lots 
of unknowns, so that's why I'm seeking the advice. 


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