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.