New iPhone BootROM Vulnerability Exposes Apple SoCs to Full Chain-of-Trust Compromise

Paradigm Shift disclosed "usbliter8", a BootROM-level vulnerability in the Synopsys DWC2 USB controller on Apple A12, A13 and S4/S5 SoCs that enables a DMA-based buffer underflow and arbitrary memory writes; researchers produced a proof-of-concept exploit that achieves SecureROM/EL1 code execution, disables signature verification to boot unsigned iBoot images, and cannot be patched in affected BootROM silicon—migration to A14+ hardware is the only effective mitigation.