I'm currently using a hacked/unlocked iphone (Quickpwn) & have been doing for the last 6 months.
At present I'm on a monthly contract with T-Mobile but looking to change to another network as I'm getting a work phone.
I've tried inserting an Asda SIM but get a 'No Service' indication from my phone (the Asda service runs on the Vodafone network so has 99% UK coverage).
I wondered if it was a dodgy SIM so tried a number of others (O2, Orange & Vodafone) but got the same problem.
I then wondered if it was anything to do with me leaving the T-Mobile SIM in when I hacked the iphone so tried a couple of other T-Mobile SIMs & hey presto they worked!
I tried inserting a non-T-Mobile SIM to see if that had cured it but noooooooo
This drove me to do a complete restore & re-jailbreak but its still the same!!!!
I'm currently on firmware 2.1
Any advice anyone before I pull out whatever hair I have left!!!