[Q80]

How do i do this ?

[tooki]

Download the correct 3.1.2 IPSW file (the internet can find the link for you), then hold down Option (I think) when you click Restore in iTunes, then you can pick the IPSW you want to use, so use the one you downloaded.

In fact, it might still be on your computer. I don't remember the name of the folder where iTunes stores the IPSWs, though.

[karent]

just curious, why would you want to roll back? something wrong with this version I should know about?

[Q80]

my friend gave me an iphone, i never used it(4months) power it up and it says "the sim card inserted in this phone does not appear to be supported".

so i am trying to get it down to 3.1.2 to get it working if u know what i mean

I was told to get some info specifically.

Settings > General > About > Version (I need that one) > Modem Firmware Version (I need that, too) > iPhone Baseband Version (and i need that lastly).

[tooki]

If you needed help to know how to downgrade the firmware, you're gonna have a devil of a time unlocking it, since the process and software to do it have incredibly lousy documentation. Search for how-to guides… somewhere else!