Baseband Bootloader

The baseband bootloader is the code which runs before the baseband FW, it is responsible for signature checking and updating the baseband. See also bootloader.

3.9
This is the old bootloader from the iPhone/S-Gold 2. It is vulnerable to Minus 0x400 and IPSF

4.6
This is the new bootloader from the iPhone/S-Gold 2. It is vulnerable to Minus 0x20000 with Back Extend Erase

5.8
This is the bootloader from the iPhone 3G/X-Gold 608. Currently it has no known exploits. It is, in contrast to 3.9 and 4.6, sig checked on startup.