Every time I try to use the tool, I get to 56% of writing the save to NOR, and it always freezes there, so long as I'm trying SoulSilver or Platinum. Another random game (CrossworDS) froze at 50%.
The hwtest.nds output for my 3-in-1 is as follows:
Testing 512M version:
ffff ffff ffff ffff
Testing 256M versions:
227e 227e
Testing 256M revision:
2218 2218
H6H6
I'm using both an EDGE (latest firmware) and an EZ Flash Vi (latest firmware) on a DS Lite.
UPDATE
And now after fiddling about with it for another half hour, I was able to get it to work after backiing up a Pokemon Diamond save using Rudolph's 3-in-1 tool, though when I first started said tool, it was giving me errors about not being able to see the 3-in-1.
So..yeah, used the Rudolph 3-in-1 tool to reformat my 3-in-1, and was able to get Snapshot 2 working and was able to backup and edit and restore my SoulSilver save.
2.2 probably works, just.. haven't tried it.