First off your first partition has to be less than 4 GB in size so that the scsi.device in ROM can see it to boot. Then in the startup-sequence you can have LoadModule load the latest scsi.device so that when the the Amiga warm reboots during startup the new scsi.device will be used allowing you to see your HD properly and use larger partitions.
You need the latest scsi.device copied to your DEVS: folder, you need the latest loadmodule copied to your C: folder and then you need to edit your startup-sequence to add above the Setpatch line
C:LoadModule AUTO NOREBOOT
and edit the setpatch line
C:Setpatch SKIPROMMODULES scsi.device QUIET
