johnnycontrario wrote on 2020-11-25, 06:19:

When I had the problem with the 8GB drives, I didn't immediately discover it because I had prepared my 8GB SD card with DOS and Win 3.1 via a VM. I actually used that SD card in my 486 for a long time as my test card and didn't notice anything wrong until I tried partitioning another 8GB SD card on that system. I believe I didn't notice because I hadn't used any part of the disk above the 512MB that DOS was unable to access. DOS would happily list the volumes because that data is in the area before the first partition. Sure enough, if I tried partitioning ANY 8GB SD card, including that one that was 'working', DOS could only see a 512MB disk. Nothing worked despite the BIOS auto-detecting the correct geometry every time. Your false starts may be due to a similar issue.

I have a FIC 486 MOBO with BIOS that has detected the correct C,H,S settings for drives between 528MB & 32GB for me, and I can boot from a floppy to partition & format the drives, but the motherboard won't boot from the drives without overlay software.