I had tried to resolve my issue with a Rut200 after attempting a firmware upgrade, I am almost 100% sure it has lost its manufacturer information as per this post and steps followed here:
I did the mnf_info -mtnwbv cmd and also got FFFFFFFFFFFF and UNKNOWN
I am able to access the admin interface via 192.168.1.1 but cannot use the sim or anything.
I have sent you a form to fill out. Once it’s completed, I will contact you privately to arrange a remote session. Please use Ticket ID “14398” as a reference.
I apologies for my above message there was an error in my explaination, however I am still having an issue with my device getting the name “UNKNOW” and showing UNKNOWNXXXXX