A blog post - arguably the information is a couple years past relevance, but it's been sitting in a draft in google docs so I decided I may as well publish it somewhere discoverable.

https://n1cck.us/blog/unlocking-anytone-878/

Unlocking the AnyTone 878

The various steps needed to unlock your Anyton 878 and derivatives to use the full frequency space of the internal chip.

Nick Booth