A couple of questions

[Tigerbite]

I just bought an iPhone 3gs off of ebay that's already unlocked. Is there anything I should know to keep from breaking the unlock other than the obvious (don't upgrade.)

If they battery dies will that break the unlock? Let me know if there's anything I should avoid to keep from breaking it! Thanks.

[iamkadaj]

If it's factory unlocked you're doing great, if it's not, then it's unlocked via UltraSn0w through a jailbreak...

The only way it'll mess up is if it's a tethered jailbreak, meaning every time the battery dies it has to be kick started whilst connected to your computer through a Jailbreak tool. It'll just stay on the boot screen/apple logo until connected. (very annoying!)

If that's not the case and it's untethered, just stay away from updating the firmware, and don't mess around with Cydia if you're unfamiliar.

That's it really

[Tigerbite]

Well, it's for my girlfriend (of course T-Mobile decides to merge with ATT 2 days after I buy the phone for her, lol.) So I'm just trying to figure out what to tell her NOT to do

[i.Annie]

First thing you should do is save your SHSHS NOW. that way if anything happens in the future, you can restore to a custom firmware to preserve your baseband to prevent losing your unlock.

If the unlock is with the iPad baseband (check in settings, general, about under modem firmware) of 6.15.00 then you can't lose your unlock. However, you cannot restore to a stock 4.2.1+ firmware or you'll get stuck. So If you do have that baseband version, be careful not to mess around with your phone too much with Cydia like ^ said, so that you can avoid having to restore.

Back to saving SHSHs, go to Cydia and hit the "make my life easier" button on the home page. Also go download tinyumbrella from thefirmwareumbrella.blogspot.com and click save SHSHs.

This way you can get SHSHs for 4.3 so in the future you will be safe.

[Tigerbite]

Okay, I just checked the modem firmware and it's 06.15.00

So there's nothing to worry about? I heard some things don't work with that baseband? Is that true and if so what exactly doesn't work with it?

[Stray]

True GPS based apps will not work