I have a Zyyxel VMG8924-B10A bought of ebay. The previous owner upgraded it to version 16 of the firmware. I had it connected to Vodafone VDSL, and unfortunately I decided to reboot it remotely. There was no reboot option in the menus but I did find there was a cli reboot command. When I used this command the last thing I saw was "resetting". I did ask Vodafone if they could restart the line, when they tried to do this they asked me if I had any connection with Zen!
I now have physical access to the router and can find something about Zen in the connection userid field. When I tried to restore a saved configuration it told me it was invalid. This lead me to finding that the router had reverted to firmware version 15 and everything that I had configured was lost. I reloaded version 16 and was then able to restore my most recent saved configuration.
So how does a VMG8924-B10A hold two configurations and know which one to use?
I have a 2nd ebay VMG8924-B10A when I reboot it, nothing changes!