A link wouldn't help... One cannot revert firmware on a prime, only move forward
Since you mentioned the tuner light flashing, I would make sure you have enabled reporting and respond back with device id and time the error occurs (if it was already turned on in the past week, you can probably just mention the time of the last occurrence) and hopefully nickk can look it up or you may use their trouble ticket system. With exception of you mentioning that led, it seems to me that it is a DRM issue of view on the fire TV or perhaps the cablecard beginning to go out since both times you mentioned the problem as having another device also tuned to the channel... do your logs say anything? Also since you mentioned cox, do you happen to be in kansas as they have been having some strange cablecard problems reported there recently.
You may also wish to try another power adapter
as typically the first symptom is a bad signal when 2 or more tuners are in use and/or on one particular tuner.