Hi
I am having the exact same issue. I enjoyed an unlocked 3gs 3.1.2 (blacksn0w) for about 2 months and then I started having WIFI issues. I reset my network settings as many sites suggested, but doing that put my phone into a boot loop stuck at the apple logo (thx guys). I was forced to restore the phone with a custom 3.1.2 pwnagetool firmware and I ran blacksn0w again. It worked this time but about a week later, the phone crashed again and when I restarted it, it was in a boot loop.
After the 2nd restore, blacksn0w no longer unlocks my phone but rather just makes it extremely slow and unstable for a min or so and then completely freezes. Restarting just puts it in a boot loop. I have tried installing blacksn0w via cydia and manually without results. I've restored and reblacksn0w'd multiple times and it crashes every time.
It's odd to me that the unlock worked for a while, then worked again after 1 restore, and now just completely doesn't work. I don't understand what changed with the phone when I never upgraded to another firmware or made any other os modifications. I don't have my 3.1.2 shsh on file, so doing an original restore is out of the question now
Has anyone had any luck solving this problem?
I am sorry to hear that but I don't have a solution. However, I am seeing myself in your boat if I use blacksn0w to unlock. I have read so many issues w/ unlock using blacksn0w. nothing about jb though.
And unfortunately, no one seems to know an alternative for blacksn0w or may be just no alternative to unlock an iphone. For example, I learned that redsn0w can be used to jb instead of blackra1n but then eventually need to use blacksn0w to unlock it. The iphone dev team has developed reliable tools to jb but depend on the buggy geohot blacksn0w software to unlock