MR6110 Won't boot anymore

My router worked fine for many months but then froze and won't boot past the 'Netgear' screen.

Power cycling and switching between mains and battery doesn't help.

The reset button has no effect.

Reseating the SIM doesn't help.

I was looking to download the firmware and try TFTPing it to see if that helped but I cannot find a copy of the firmware for the router anywhere online.

So, totally stuck. Is the device bricked? It's not even 1 year old yet.