Mark Rages wrote:
> For a bootloader, my misconception makes as much sense than the way
> the PIC actually works.

For a bootloader, you leave program memory write enabled.  The write disable
is for extra security for programs that do not try to write over themselves.

> Imagine a program that writes zeroes to all the WRTx config locations.
> This will entirely disable a bootloaded device as surely as
> overwriting the bootloader would.

Right, so don't do that.  These bits aren't meant for bootloader
applications.  They are meant to guarantee that a program can't scribble on
itself.  There are already some safeguards to make it unlikely random code
can write to program memory, so these bits provide an absolute way to
guarantee it.  Allowing them to be reset from the program would defeat the
purpose.  That would be similar to a watchdog timer that could be disabled
under software control.


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