I'm currently on H6 firmware, and I'm pretty much unable to do ANYTHING with regard to updating/rooting/flashing/whatever-ing the phone, as the drivers I have installed don't seem to work.
See my post here:
http://androidforums.com/samsung-i7500/10109-modaco-custom-rom-based-ih8.html#post61387
for a full description.
If any of the super-users here can point me in the right direction with getting the PC connected to the phone in FASTBOOT mode, I'm gonna just put the MoDoCo ROM on for now.
Cheers.