git clone https://github.com/axi0mX/ipwnderfu (or a fork like pwndfu2 )
The BootROM is read-only memory (mask ROM) etched into the silicon during manufacturing. Apple cannot issue an OTA update to fix a hardware flaw. The only way to fix Checkm8 is to release a new device with a redesigned chip (A12 and later are immune). Pwndfu Mac