[flajpan]

Na windowsima ovak:

To check iPhone 3G/3GS bootrom version:
Put your iphone in DFU mode.
(Connect your iPhone to iTunes, turn off, click power+home button for 10 seconds, leave POWER button after 10 seconds, holding HOME button)
iTunes will detect your iPhone in recovery mode.
Go To:
Start->Control Panel->Device Manager
In Universal Serial BUS Controller, you will find Apple Mobile Device USB Driver
Right Click and go to Properties, go to Details tab and select "Device Instance Path" from the drop down list box.
In that information, u will find [iBoot-359.x] at the end.

Ili ako je jailbreakan, samo ga restartaj, ako se normalno upali imaš staru verziju, ako traži restore (ona slika s kablom) onda imaš novu.