This is the device in the iPhone and iPad that manages all the functions which require an antenna. The baseband processor has its own RAM and firmware in NOR flash, separate from the ARM core resources. The baseband is a resource to the OS. The Wi-Fi and Bluetooth are managed by the main CPU, although the baseband stores their MAC addresses in its NVRAM.
The iPhone's baseband processor is the S-Gold 2. The iPhone 3G, the iPhone 3GS and the iPad make use of the X-Gold 608 chip for this purpose. The iPhone 4 (iPhone3,1) and iPad 2 (iPad2,2) use the XMM 6180, while the iPhone 4 (iPhone3,3) uses the MDM6600 and the iPhone 4S uses the MDM6610. iPad 3 uses MDM9600. iPad 4, iPad Air , iPad mini, iPad mini 2, iPad mini 3, iPhone 5, iPhone 5c and iPhone 5s use MDM9615 while iPad Air 2, iPad mini 4, iPhone 6 and iPhone 6 Plus use MDM9625. iPhone 6s and iPhone 6s Plus use MDM9635.
This is the area in the baseband where the lock state is stored.
0x400--NCK token 0xA00--IMEI signature 0xB00--IMEI 0xC00--Locks table