the firmware folder is /storage/.config/firmware/
There is a wiki how to do it.
after reboot you should see a different version
Thank you! With your instructions, it's now finding some services using downgraded 4.0.11 firmware.
Although oddly some of the Freeview transponders are not returning anything, so I guess I'll try a few different firmwares, has anyone else got issues with some of the frequencies?