Unpatchable 'usbliter8' Exploit Breaks Apple A12 and A13 SecureROM Boot Chain

The 'usbliter8' exploit exposes a fundamental hardware vulnerability rooted in a third-party Synopsys USB controller embedded in Apple's A12 and A13 chips — a classic supply chain risk where a component vendor's flaw becomes the product owner's permanent liability. Because the vulnerability resides in the SecureROM (read-only memory), no software patch can remediate it, leaving affected devices permanently exposed. An attacker with physical access can trigger the exploit via DFU mode to bypass Apple's trusted boot chain and execute unsigned code, undermining the device's core security guarantees. This matters because it demonstrates that even well-designed secure boot architectures can be defeated at the silicon level when third-party component security is insufficiently vetted.