I purchased a model A9M0107 5.25" drive off of eBay for my ROM03 IIGS. I've used ADTPro via serial to successfully write several disks, but GS/OS cannot read them. I'm using a box of Dysan 5.25" disks new old stock, shrink wrapped. Double sided, Double Density.
Example, if I try and initialize a blank floppy in GS/OS 6.0.1 or 6.0.4 - I goes through the motions and then at the end, it says "Unknown Error $00A8". I did notice for some reason GS/OS 5 works. I'm using OS images from "What is the Apple IIGS?" website via my BOOTI card. I can boot from MECC Inspector, Locksmith 6.0 and Master Diagnostics IIe disks I created via ADTPro - all say the drive is fine, yet GS/OS 6.0.1 and 6.0.4 can't use it. I've tried having the 5.25" drive connected directly to IIGS and also via 3.5" drive, same issues.
Any ideas? Thanks!