reset admin password without answer to security question?

MHS800L (fcc: XHG-R800)

I bought this device second hand. I have registered it to my verizon account and the wifi password displays. The admin password is not the wifi password. I do not know the answer the the security question either.

Verizon wireless support was unable to remotely reset the admin password. I would very much like to increase the wifi not-connected disconnection timeout and change the wifi transmit power. The device needs to be inches from my laptop. :(

How can I reset the MHS800L admin password?

No combination of power button or power reset button do this according to the manual or tedious experimentation.

The manual facetiously suggests I login with the admin password (which I don't know) to change the admin password or factory reset.