I would like to know more about basebands.
- Does it change when updating iOS?
- Do all iPhones have the same baseband?
- If not, how do they differ?
- And ... can I unlock an iPhone 4 with iOS 5.1.1?
I would be very grateful for an explanation.
Q: Does it change when updating iOS?
A: Yes, the firmware is revised and is packaged inside the software update archive.
Q: Do all iPhones have the same baseband?
A: No. They get updated and iPhones can have one of multiple chips with incompatible firmware.
Q: If not, how do they differ?
A: Bugfixes, security patches etc. Different generations have differing chipsets as well.
Q: And ... can I unlock an iPhone 4 with iOS 5.1.1?
A: Yes, you can use ultrasn0w for a software unlock if your iPhone 4's baseband is 01.59.00. You can check your baseband version by going to
iPhone 4 Chipset Page: http://theiphonewiki.com/wiki/index.php?title=XMM_6180