I have just jailbroken my iPhone 4 with green poison. I love all the things I can do with it, but I'm having problems with my battery draining way too fast now. Also having a lot of problems with safari crashing all the time! I clear all my history, cookies, and cache daily and reboot. I'm not sure if I have put something on my phone that is causing all these problems. Should I just unjailbreak? If so how do I do it? I tried restore on iTunes and everything stayed the same! Or can I just erase all my jailbreak stuff, and start over? Any suggestions would be great! I did look for a specific thread, but was unable to find one so before someone yells at me, you can just point me in the right direction. Thanx in advance!
Do a restore as new device. This will reset your device back to a new state but it will likely upgrade you to 4.3 which only supports a tethered jailbreak right now. You will want to see if cydia has your 4.2.1 shsh blobs before doing this.
Same thing happened to me.
I restored to a custom 4.2.1 firmware i downloaded and once finished it was in DFU mode it wouldn't come out.
I had to jailbreak with greenpoison when it was in DFU mode and it worked perfect.