i have the latest version of redsn0w which is the same version i used to JB when i was at 5.0 .. my phone locked one day and I had to do a full restore, i was forced to upgrade to 5.0.1 via iTunes...
I tried to run redsn0w after that, but it says it can't and suggest I load a custom IPSW file. I also tried acidsn0w, but that program was a joke. the assistant is not so helpful.