Sylnar v1.1.34

Fixed

• A flash whose erase does nothing no longer writes a corrupt image. Until now
  Sylnar noticed the erase had not happened, said so, and then spent three minutes
  writing anyway. Writing to flash that was not erased can only ever produce a
  broken image, so the board could not boot from it. Sylnar now stops at the very
  first page, before anything of substance is written, and starts the flash again
  from the beginning. It tries up to three times.
• If all three attempts fail to erase, Sylnar writes nothing at all and says so.
  The board keeps whatever was on it rather than being left unbootable.

Why three: the same board has been seen to erase properly on one attempt and do
nothing on the next with nothing else changed. The cause of that is still open,
and every attempt is recorded in %LOCALAPPDATA%\Sylnar\flash\.