(adsbygoogle = window.adsbygoogle || []).push({}); My cousin got an iPhone 3G (don't think it's 3GS) which he asked me to jailbreak (which I did). Problem is, the phone is baseband 05.15.04 which means unlocking carriers is supposed to be an issue.

Is it worth upgrading to the iPad baseband, and what risks are involved? Not sure where he got it from, but I've already tried several carrier sims (3, Vodafone, O2) and not one seems to be working with it, so not sure if I am even able to get any sim to run in it. Or is there some other way to get it to run, as I am not well versed in iPhone jailbreaking (did it a few times with 2G phones).

bootloader: 06.04 [g2m3s2]
baseband: ice2-05.15.04
OS: 4.2.1

Is it possible to just downgrade using a custom IPSW which will in turn downgrade the baseband?

Moved to iPod/iPhone/iPad Modding.