bug: change PTYPEs to avoid clash with bootloader

ertm bootloader interprets
which is
as a very destructive command, which has consequences when cmds are
accidentally sent while the board is in bootloader mode.

This takes care to avoid this kind of collision and the ensuing
deletion of firmware/bricking of the board.
Signed-off-by: Juan David Gonzalez Cobas <dcobas@cern.ch>
Reported-by: Tomasz Wlostowski <twlostow@cern.ch>