Baseband (aka modem) is an iPhone radio module responsible for cellular communications and GPS. It works on its own firmware, which is installed and updated during the flashing of the device in parallel with iOS itself. Often, instead of the phrase “modem firmware” they say and write simply “modem” or “baseband”. The main information that concerns everyone who cares about unlocking the iPhone is the version of the iPhone modem. As a rule, it is the modem version that determines the possibility of software and hardware unlock.
- - How to determine the version of the modem on the activated and activated iPhone?
Settings ->Major ->About this device ->Modem firmware **. **. **
- - How to determine the version of the modem on a non-activated iPhone?
You will need->redsn0w (for
OS X and for
Windows ). Run the program and connect your iPhone - below you will see the iOS version and the modem firmware version in brackets separated by commas:
- - How are the modem version and the iOS version?
Each version of iOS for iPhone contains some modem firmware. It often happens that the new version of iOS contains the old version of the modem. At the same time, iOS can work with almost any version of the modem besides the one that should have been installed with the appropriate firmware. This gives users the opportunity to upgrade to the latest firmware, while maintaining the old versions of modems that can be unlocked. To update the iPhone without upgrading the modem (relevant for older devices ->
iPhone 3G / 3GS / 4 ), you will need a custom firmware. More in topic ->
Creating custom firmware - - Is it possible to lower the version of the iPhone modem?
Modem downgrade is possible for devices ->
iPhone 3G / 3GS . More in topic ->
[FAQ] Rollback and unlock instructions