This post is old and is not updated (I’ve moved on to Android). Comments are now turned off. For more details on jailbreaking and unlocking, please visit http://jailbrea.kr/ and http://unloc.kr/
Dislcaimer: I’m NOT responsible in ANY way if you damage your iPhone. This will require you to open up the iPhone to verify the SIM slot which will void Apple Warranty. So DON’T do it if you are unsure.
If you are among the unlucky ones who happen to jailbreak and unlock your iPhone 3G to get cellular network access, you might have come across this annoying problem. For most, installing ultrasn0w and a simple reboot works. But for many, it just doesn’t! No matter what you do, you will be facing the dreaded “No Service” or “No SIM card installed” problem.
I have been playing with my iPhone 3G for about a month now, and was suffering the same fate. No matter what I tried, it JUST WOULDN”T WORK! I knew I was following the jailbreak and unlock steps correctly, so I decided to give it to a service center and get it checked. And voila! A piggyback unlock chip i-Smartphone was soldered to the SIM slot inside the phone! To complicated the matter, it was done in the sloppiest way possible with wires hanging all around (apparently some old technique). This seems to be the issue with many phones originating from Australia and the middle east (as mine did), so if you got your iPhone through the Grey channel and are facing problems, this might be it.
How do you fix it? Simple - After removing the soldered chip, I restored my iPhone with a custom OS 3.1 firmware using pwnage tool, installed ultrasn0w, and it just works! The problem is the conflict between software and hardware unlock techniques. Hardware unlock is buggy, troublesome and not recommended especially because ultrasn0w works perfectly now!
So there you have it. If you are sure that you are doing the jailbreak/unlock right but still aren’t able to get into your network, try this. If this helps anyone, leave your comments and experiences please.
P.S: If you take it to an Apple store to get it fixed, they will reject it outright as any hardware/software modding on the iPhone violates the warranty. So my advice is to avoid Apple, and get your friendly neighborhood mobile service guy to check it.
Update 1: If after doing all this you still get “No Service”, goto Settings -> General -> About and check the field “Carrier”. If it shows your service provider (ex: Airtel 5.0) then there maybe some problem with automatically selecting your network. To do it manually, Goto Settings -> Carrier and let the list populate with the service providers in your area. Then select your network from that list. To verify, reboot the phone and see if it sets automatically.
Update 2: If you use pwnage tool to jailbreak and install custom OS 3.1 (which you should, if you don’t want to lose your unlock) the name of the carrier will not show up at the top left, right next to the signal indicator. It is a known bug and you can simply set your custom carrier label using a tool called “MakeItMine” which you can install through Cydia.