Hey this is my first time posting about an iPhone issue and I'm not so sure if I'm posting correctly or if I'm in the right place for this topic but I need some help and after quite a lot of looking around I have yet to find anything to help me so here goes.

I have an iPhone 4 GSM that was running smoothly 3 or so days ago on 4.2.1 with bb 03.10.01 and I was about to do my own screen repair on it but wanted to jailbreak it first so I did this using redsn0w 0.9.8b4 (I think) and all was well! The phone worked great an then I realized after downloading ultrasn0w that the bb 03.10.01 cannot be unlocked so I did more research and somewhere I saw that if you jailbreak 4.2.1 and 03.10.01 using the newest limera1n you would be unlocked and jailbroken so...I tried it..I have No SHSH blobs saved and now I have taken quite a tumble down the rabbit hole. The iphone came back with a black screen so i tried to exit recovery via TU and RecBoot and anything else I could find bit nothing. I plugged the phone intothe computer again and ran redsn0w and boot tether and presto! The phone came back on! I set it down next to me for all of about 30 seconds I'd say and the screen was black again so I did a boot tether again and then I got noises from the phone and could toggle the vibrate switch on and off ect. So i think "ok I have a screen to throw on it'll be fine" but now I have tried to boot tether and all I get is an pineapple for a few then back to dfu. iTunes restore stock Ipsw (current firmware) dfu, tried to upgrade to anything above 4.2.1...dfu, changed hosts file to fix errors, TSS in TU on, off, you name it I am 98% confident I tried it and no luck. I have a beautiful practically brand new iPhone 4 white conversion DFU coaster....please if anyone can help me restore this phone to ANY firmware I don't care if I can't jailbreak it or unlock it for the rest of my days I just want it to be working...sorry for my long sob story and thanks for your help!