Hi there, Apologies if this post is lengthy. I own an iPhone 3GS (16GB) that was originally locked to the 'Orange' network. It's been running unlocked on 4.2.1 perfectly with iPad baseband for about 4-5 months now (I even had working GPS). However, yesterday I came across a problem. I noticed that I had no signal bars, yet my carrier was still displayed. I live in quite a high signal area, so this was new to me. Upon further inspection I discovered that I could not make/receive calls or SMS messages. After playing around I discovered that if I turn off all data (3G and Cellular Data) my phone displays 'No Service'. When they're turned on, I will either get a 3G or Edge Logo and 'O2-UK' displayed. Here's where the interesting part comes in. Turns out that I can use all my data fine. Even though it's reporting no bars, I still get the effects of a full 3G connection. I'm basically only able to use my data connection and nothing else. After ruling out my sim card by trying it in another phone, I began to search around for a solution. I am aware that upgrading to the iPad baseband is a huge risk. However when I received the phone it was my only option for an unlock. While many people have similar problems, I don't think i've seen one where only the data side of things is working. Whilst trying to restore my phone and repair this issue I ended up with a bricked phone, stuck in a DFU Loop. I tried almost every combination of redsn0w/Pwnage Tool/Greenpois0n/Custom Firmware possible. After hours of failed attempts, I was finally able to use redsn0w to put my phone into a pwned DFU mode, install the stock 4.3.3 firmware (with 1015 error ofcourse) and Jailbreak successfully (again, with redsn0w). I also used ultrasn0w to unlock after this however have exactly the same issue except now i'm on 4.3.3 rather than 4.2.1. Unfortunately I do not have an Orange sim to check that it's not hardware, but I find that unlikely as I look after this phone very carefully and my issue appeared out of nowhere. If anyone has experienced anything similar or has any suggestions, i'd be interested to hear. Thank you.