Not for 32-bit, although fair point for 64-bit. That said, an iBoot-level backdoor may not be as useful these days, considering Data partition is still protect

Not for 32-bit, although fair point for 64-bit. That said, an iBoot-level backdoor may not be as useful these days, considering Data partition is still protected with passphrase (and 10-attempt limit being SEP-enforced now). I suppose you could argue root filesydtem access would be a concern, yet you would still need multiple zero-days to get persistence, defeat CS, etc. While the argument regarding auditing is valid (for 64-bit), we both are aware that certain parties have privately been able to decrypt those. I highly doubt they would not say something if they had discovered a backdoor in iBoot.