So, I was getting kind of angry with app crashes and my phone running slow, so I wanted to update to 4.2.1 and then re-jailbreak using greenpois0n. I got everything restored and ready, and then followed the instructions on greenpois0n's program, and the phone pretty much died. I had to completely restore and redo everything in a huge like 3 hour process. I then tried again. Same thing seems to be happening. What am I doing wrong? I have a 3GS, and I'm using a mac to do this. I have the phone off and plugged in when i start greenpois0n. I follow the instructions. Why is it basically killing my phone? I don't want to have to use this thing non-jailbroken.... I've become way too used to lockinfo.
Edit: Derp, I think I found my problem... I'm on an iphone 3G. How can I jailbreak a 3G with 4.2.1?