Iphone 3g unlock questions

[Adams7722]

Hey everyone, just have a few questions about unlocking an iphone for use in Canada, I recently bought an older 3g to use on Bell, (iphone is sim locked to at&t) with ios 4.2.1 and baseband 05.15.04, I have read that this bb is not unlockable currently but one can use pwnagetool 4.2 (im on a mac) to install ipad bb 6.15 to unlock through ultrasnow, however I have also heard that changing to this bb can cause problems. Since voiding the warrantee is not an issue and 4.2.1 being the last 3g update, is it safe to just go ahead and update to this bb? Or could this potentially cause problems with the phone in the future? Any ideas would be appreciate, thanks

 

[eastercat]

You lose GPS functionality. You will always have to restore with custom firmware; you'll never be able to use itunes to install firmware. If you look through the threads, you'll find other people who elaborate on issues with the ipad bb.