http://www.hasselbladdigitalforum.com/index.php?topic=4381.0 and download the linked pdf.
Basically, the version II is the one you want as its firmware can be updated.
As to which version can be used on the H1, H2, etc... that probably depends on the firmware of these cameras (which can be updated).
Thanks, this was the exact link I stumbled upon earlier. I didn't see any link to download a PDF, also I suspect OP is not looking for the answer I am looking for, from the reply it seems that OP is looking for difference between HVD 90X and HV 90X-II, but I am specifically looking for the difference between HV 90X and HV 90X-II.
Actually I just found this info from the H4X manual:
- HV 90x: 90° eye-level viewfinder w. diopter adjustment (-4 to +2.5D). Image magnification 2.7 times. Integral fill-flash (G.No. 12 @ ISO100). Hot shoe for SCA3002-system flashes from Metz™
- HV 90x-II: 90° eye-level viewfinder w. diopter adjustment (-4 to +2.5D). Image magnification 2.7 times. Integral fill-flash (G.No. 12 @ ISO100). Hot shoe for SCA3002-system flashes from Metz™
- HVD 90x: 90° eye-level viewfinder w. diopter adjustment (-5 to +3.5D). Image magnification 3.1 times. Integral fill-flash (G.No. 12 @ ISO100). Hot shoe for SCA3002-system flashes from Metz™
- HVM: Waist-level viewfinder
It seems that HV 90X and HV 90X-II have identical specs, I wonder what changed...