Hi, forgive my ignorance and limited knowledge but I have an Iphone that is jailbroken to accept any o2 sim. It has a simplicity sim in it that works a treat. Can I upgrade to firmware 1.1.4 through itunes or will it lock my phone up?
Thanks

Next time search but here is what you should do restore to 1.1.4. It will relock and unjailbreak your phone. When its done run iplus2.0b or pwned if you have a mac

Dont forget the edge settings for O2 uk, you will get them here

http://www.modmyifone.com/forums/showthread.php?t=28249

You will need to learn SSH, but there are many tutorials on this.