Hello iPhone Gurus - hope this isnt too much of a newbie question - looking to buy a used 3g on Craigslist or ebay to replace my son's original iPhone.

When I am asking the current owner what os & modem version they are on and they have already removed their SIM - how can I determine the critical versions its running? - I need it to be un-lockable to use on Tmobile. -thanks

Originally Posted by joelr

Hello iPhone Gurus - hope this isnt too much of a newbie question - looking to buy a used 3g on Craigslist or ebay to replace my son's original iPhone.

When I am asking the current owner what os & modem version they are on and they have already removed their SIM - how can I determine the critical versions its running? - I need it to be un-lockable to use on Tmobile. -thanks

They can plug in the iPhone to their computer (which should have iTunes 9 or 10 installed) and then use TinyUmbrella The Firmware Umbrella - TinyUmbrella to find out the baseband (modem version) OS and baseband bootloader - even without a SIM card inserted or without the iPhone activated. It does need to have iOS installed (so if they used erase all content and settings, they would need to carefully install OS 3.1.3 or lower on the iPhone).