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

[rescue]

Didn't hacked or 3rd party cd-rom drivers exist.  That won't handle the 
boot problem, but the boot checks might not be as thorough as Disk Setup 
???

Plextor CD-ROM SCSI drives used to have a 512 byte block jumper as 
well.  I don't know about the DVD drives.


On 2016-06-15 16:45, Swift Griggs wrote:
> 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
> fact.
>
>> 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.
>
> -Swift