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Unlocked Galaxy i7500, Reset Will Remove it?

Possible Duplicate:
Will resetting my unlocked phone to factory settings lock it again?

I just purchased and unlocked a Samsung Galaxy i7500 using FastGSM's system. (It cost $20 and it's used up; I can't redo it.)

I know my phone has an option to "reset" it to the default/factory settings. Will doing so re-lock my phone? Is the lock hardware-level or OS/software-level? Can I upgrade the OS now that it's unlocked?

I noticed my app running a bit more slowly after unlocking, too... I just want to understand what level locking is on.