There is way too many new comments on this post for me to follow, but just a couple quick thoughts:
- I haven't had any problems using a 4GB CF card on mine. It's partitioned 300MB OS/1.8GB Work/1.8GB Games. Always keep partitions under 2GB if using FFS. Haven't had any issues that would limit me to 3.67GB, but I believe without the GuruROM you're limited to using a total drive capacity of 4GB or less.
- Since I bought my unit from Europe and was never able to find a North American power supply, I modified it using the instructions on this page:
http://members.iinet.net.au/~davem2/overclock/a500hd.htmlto draw power from the A500's internal connector. This worked fine for both the 80MB drive my unit came with and my MechWare SCSI card reader. I wouldn't try to run a newer, more power hungry drive this way, however. Maybe one that's slower though (5400 RPM) as opposed to 7200 RPM might work. Same thing if you're using the GVP power supply - try to stick to a less power-hungry drive like Zetr0 says, or a CF card.
- You can find out your ROM version by looking at the GVP motherboard. It's the only socketed chip on the board and should have a sticker on the top. Alternatively I believe SysInfo reports the ROM version, as well.
- I don't recall what version of HDToolbox works with Workbench 2.0, but again my .02 cents is to upgrade to 3.1 (ROM is about $15 on ebay or AmigaKit, disks can be downloaded from lots of places). I found the 3.1 HDToolbox much easier and more intuitive to use than the GVP ExpertPrep/FaaastPrep utility.
Good luck!