I got rid of FFS ages ago and installed Smart File System. I run a 10Gb SCSI Seagate with no problem using SFS with OS3.5. Also try using SCSIPrefs to set the drive to synchronous transfer. Check your motherboard battery too. Are you using the WarpEngine SCSI or motherboard SCSI? Your boot partition should be in the first 2Gb of the drive and under 2Gb in size too. Hope that helps you.
I would never throw my A3k in the closet! :-P
