Updating unlocked iphone 2g
This is somewhat rare, but if an i OS update is interrupted it can happen, which usually requires a device be placed into DFU mode and restored manually with firmware.
Typically a normal i Tunes based restore is sufficient, which is why that is fairly rare.
Also, for users with many of the same i OS devices, having a single IPSW downloads let’s you conserve bandwidth by applying a single update to many devices.
Rarely, firmware files are required to restore a malfunctioning i Phone, i Pad, or i Pod touch that is basically bricked, but still functional.
Going the IPSW route can take longer to update than using the newer OTA (over the air) method, the reason being that OTA uses smaller delta updates than the larger IPSW files, which are the full sized downloads and are often literally 10x the download size.
For this reason if you ever need i Phone warranty service, be sure to unjailbreak your i Phone before taking it into Apple.
Not all versions of i OS IPSW will work on all devices, so be sure to select the proper version for your hardware, and to use the latest which is supported.
Wondering where you can get all the older i Phone firmware files from?
Finally, there are some cases where IPSW is necessary to create custom configured firmware for future restores.
This typically ties in with the “Restore” method of updating, which allows the use of custom IPSW files, and is generally something created with a third party application like Pwnage Tool or sn0wbreeze.
If you are unsure of the type of i Phone, here is how to check if an i Phone is a GSM or CDMA model.