Some time back my 68000-based OS/9 system died and I needed to get stuff off the 3.5" floppies I use to back it up.
I'm a Linux user, so I used setfdprm to fiddle with the parameters in the 'floppy' driver and was able to image the disks successfully and then use the os9exec OS/9 emulator to access their contents.
The reason I'm mentioning this is that I used a standard Linux driver, which normally uses 512b blocks and a standard 3.5" drive to read OS/9 floppies while the parameters needed to read the OS/9 floppies were:
hd sect=34 ssize=256 head=2 cyl=80 tracksize=8704 dtr=0 zerobased
I haven't yet tried it on any Flex-09 disks: mine all use single density for track zero and deduce the format of the other tracks from its contents. I wrote the drivers and may have diddled with the formatter when I replaced the original two disk FD card with a Windrush card that that handles 4 drives off a pair of FDC chips.
I'm posting this to say thanks for writing such a good "get out of jail free" utility and as an indication to any other Linux users of just what setfdprm is capable of.
Martin