resetprop overrides for ro.boot.* props don't survive reboots. On
devices where the kernel doesn't set ro.boot.vbmeta.public_key_digest,
the fallback chain hit random generation on every boot — producing a
different RootOfTrust hash each time.
Added file-based persistence (boot_hash.bin, boot_key.bin) as a
fallback layer between TEE cache and random generation. Once a value
is determined from any source, it's written to disk and reused on
subsequent boots.
Verified on Redmi 14C: second boot reads from persistent file instead
of regenerating random bytes.
Enginex0
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