Amiga 1200 and IDE channel!!!

[zipper]

That is incorrect. If you are using a CD-ROM connected directly to the Amiga's motherboard (i.e. not using a buffered interface) then you do not need IDEfix. Just use scsi.device (in ROM) and the drive will be detected.

Depends on which version of OS you happen to have.

[zipper]

The original scsi.device doesn't support atapi (afair), needs to be 3.5 / 3.9. As was the situation with my A4000, IdeFix was mandatory with 3.1.