There is a bug in this release - I fixed it by running the lates version of redsnow AFTER running Greenpois0n. Only select install cydia... works a treat and stays untethered
Has anyone successfully untethered with greenpoison who has a 3GS 4.2.1 with 6.15.00 baseband? I used gp with my i4 and it worked great, when I tried with the 3 gs it failed every time. I'm wondering what I'm missing here?