Hello World, my first post on macrumors I tried searching but most of the information was not in recent time, so figured to post a new thread. I bought a used 3GS 8GB yesterday from a person. The phone is unlocked and jailbroken. Here is the relevant information: Version: 4.3.2 (8H7) Model: MC640LL Modem Firmware (baseband, i think): 06.15.00 Currently I am using it with T-Mobile, so I know it is unlocked properly. My question is.... The phone has apps and settings from the previous user. I want to 'reset' or 'restore' or something like that to remove all settings and content from previous user. If I go to Settings --> General --> Reset and perform a reset, will my phone still be usable with T-Mobile? Thank you all. Hope I provided enough info to answer.