Trusted Firmware is an open governance project[1] and you build it from source. It's not 'required' by Arm. It's perfectly possible to boot without it, as demon

Trusted Firmware is an open governance project[1] and you build it from source. It's not 'required' by Arm. It's perfectly possible to boot without it, as demonstrated by most if not all Qualcomm CPUs. [1] www.trustedfirmware.org