[Photon]

Shoulda checked my black HRM I guess. It just sounded like this code was final. In this example (see attachment), the reset instruction is unaligned.

I'm assuming the hardware makes sure the "zeropage" has something in it (even from a poweron) so that the CPU can function. Like providing a jump into ROM at the a0 target address.

There's no hope of fitting anything together with some elaborate antivirus on a bootblock. It's mostly for stopping relatively simple early viruses when testing old, unknown disks. If it prevents a resident virus from staying in memory, that's a good enough hard reset.