Question about restoring/activating iPhone 3GS

[aka757]

I recently bought an iPhone 3GS on eBay that runs 3.1.2, baseband 05.11.07, unlocked and jailbroken (untethered). Then after using a GPS app on the road the phone got hot after a while. I read that restoring the phone should fix it. So I restored with a custom activated firmware (I'm on T-Mobile) and still I see that it's having the same overheating issue. So my question is: if I try to restore using whatever default firmware is in iTunes instead of the custom activated firmware, will I be unable to jailbreak/unlock my phone because I can't activate it? Should I just try to live with the overheating issue? It doesn't get anywhere near unbearable, but it's enough to make me weary of using the phone too much (which basically means not using the TomTom app on the road). Thanks for your help.

[nagyg]

Gps seems to be a very cpu intense process. my iphone gets hot too. i don't thing you need to worry about this ....

[aka757]

Okay, but what about just playing games and regular usage? Phone still seems to heat up a bit. Does your phone heat up after 30-45 minutes of usage? Maybe I'm just being paranoid!