Does reformatting an MFM drive as RLL change the number of cylinders? I thought doing so only changed the number of sectors per cylinder. I ask because FDISK 3.3 reports 939 cylinders, even after low-level formatting (It never asked me for the CHS parameters, so I presume it just reused the old parameters). I partitioned and formatted the drive under 3.3, then booted into 6.22 and ran ScanDisk with surface scan, no errors found. FDISK 6.22 reports a capacity of 30MB. I then installed the AT&T DOS 3.3, and it seems to be working perfectly fine. Only time will tell though if this remains so.
Obviously I cannot be 100% certain since this is flimsy reasoning, but the professional manner in which the power cables were ziptied together leads me to believe this drive was likely the original (They're not ziptied in the photos because I removed the drive from the bracket for power testing before installation). Perhaps this is one of the few MFM drives that can tolerate RLL formatting with no issues?