Probably something similar to their secure boot with their phone iBoot. https://www.theiphonewiki.com/wiki/IBoot_(Bootloader) https://www.theiphonewiki.com/wiki

Probably something similar to their secure boot with their phone iBoot. https://www.theiphonewiki.com/wiki/IBoot_(Bootloader) https://www.theiphonewiki.com/wiki/IBoot_(Bootloader)