Sat May 17 22:17:00 EDT 2014

Boot block & ISRs.

Working interactively, it's a bit problematic to update the boot
block.  Especially on USB where the interrupt routine needs to be

Maybe there needs to be a routine that erases the boot block and
restores default?  Alternatively, inspect the USB ISR at boot and
reinstall if it's not there.

The easy solution is to jump into erasable space.  Though that's not
desirable in cases where the fast ISR really needs to be fast.

Let's create a .f file that copies the boot block from somewhere else.
For now it's ok to just reflash or "nop out".

Another way is to make the USB isr smart and have it detect a reset.
This way the first block after the boot block can fall into the USB

Yeah, hacking..