As above

Iphone 3G
Jailbroke with redsn0w
Activated with SAM
Software 4.2.1
Baseband 6.15.00

I have done everything I can possibly find to get this working and still it says No Service. Followed many of the threads on here and all sorts.

Basically

Factory reset the phone so its as standard
Used redsn0w to jailbreak 4.2.1
Installed ipad baseband
Unlocked with ultrasn0w 1.2.4

I've attempted downgrading baseband, still didn't work. I've rejailbroke numerous times. Also tried turning 3G off, airplane mode on and off etc.....

Please Help this is really frustrating me

I should mention I have rebuilt this phone as the digitzer and plastics were cracked.

Thanks,
Mike

Correction

This works fine with the original sim?

If i put my orange sim card in in General -> About it will state the carrier is Orange UK 9.0 but pick up no network.

If i manually try and choose carrier there is only O2 UK on there.

Original sim is O2

From this I'm guessing the unlock hasn't worked. Now the only thing I can think of I didn't do was jailbreak with the original sim in?

Cheers
Mike

Even thought it passed a bit since you post this will answer anyway. Have you tried to see if the unlock works when the iphone is hactivated with redsn0w and not activated with SAM. SAM can be tricky some times,even have to put the country , and original carrier to work.SAM must show at ActivationState: WildcardActivated if your iphone is activated.