Hmmm I thought that was an older firmware from ezvizlife site (maybe they updated it)I have only measured temps with the cover on.
Just checked again. Outside temperature is 61° F this evening.
Checked top and sides of doorbell and readings are from 68° F to 70° F. Touching top and sides of the doorbell it is not hot and barely a bit warm at this time.
I am using firmware version posted above which is:
Firmware Version: V5.2.4 build 190625
Note It is assumed that all of the hardware is the same so guessing that this firmware will work on the RCA Doorbell.
BUT it is not a guarantee that it will work and I take no responsiblity should you brick your camera.
This is the 190625 version I downloaded...
I will check mine here in the next few days, wonder how firmware could fix the heat issue.