Custom Firmware With Baseband 6.15 _best_ Today

For a long time, there was no way back. However, in 2012, the Dev-Team released a feature in that allowed users to finally downgrade from 06.15.00 back to a stable iPhone-native baseband (05.13.04). This restored GPS functionality and allowed for official unlocks through carriers like AT&T. How the Story Ends

To understand 06.15, you must understand the separation of concerns. An iPhone has two operating systems: Custom Firmware With Baseband 6.15

Once Baseband 6.15 is installed, you cannot revert to an earlier baseband (like 5.13 or 4.26) using standard methods. Attempting to downgrade often results in a in iTunes. While redsn0w can kick a device out of recovery mode, the baseband version remains at 6.15. The only way to remove it is to use a hardware programmer (JTAG) or desolder the baseband chip—impractical for most users. For a long time, there was no way back

PwnageTool allowed users to build a custom IPSW. This software modified the official Apple firmware to: How the Story Ends To understand 06