In article <604ce84e-b6ee-4f71-8416-
(E-Mail Removed)>, GilGr
(E-Mail Removed) says...
> it doesn't respond to anything, telnetting or accessing through it's
> web interface
>
I've not found anything to suggest that it keeps a copy of the original
firmware, and even if there's an internal jumper that allows you to do a
rescue flash who knows how it wants the data fed to it. Zyxel might do
it for you, try asking them.
I suspect the only way you can revert it is to take the chip out and
flash it in an EEPROM writer (assuming it's removable).