HansD

Unlimited 4KHQ and 8K recording - No mods needed!
Just know where the heat building up is coming from.
https://youtu.be/IM3ulAK5f8k

To see if there is a cheaper solution than the CFexpress card type B for the Canon EOS R5, I bought the CFexpress To SSD Converter from Zitay.
And a separate 2TB Samsung 980 Pro PCIe 4.0 NVMe M.2 SSD drive.
In total, it is still much cheaper then, for example, a Sony Tough 512 GB CFexpress card (For me 6.2 times in terms of storage capacity).
Now I can shoot 8K RAW footage up to the time limit of 29:59 minutes without getting an overheating warning!

Some people just make a small opening in the battery lid.
I just use the supplied rubber stops.

To see if there is a cheaper solution than the CFexpress card type B for the Canon EOS R5, I bought the CFexpress To SSD Converter from Zitay.
And a separate 2TB Samsung 980 Pro PCIe 4.0 NVMe M.2 SSD drive.
In total, it is still much cheaper then, for example, a Sony Tough 512 GB CFexpress card (For me 6.2 times in terms of storage capacity).
Now I can shoot 8K RAW footage up to the time limit of 29:59 minutes without getting an overheating warning!

(Water)cooled Canon EOS R5
 

If limiting skin exposure to heat is the primary goal of Canon's thermal management they should be able to easily distinguish between hand-held and tripod use via either the IBIS gyros or the camera level sensors, and use that information to establish the appropriate temperature thresholds. With some user warnings to handle the scenario of moving between tripod and hand-held use. 

43 C is regarded as the limit of temperature that is safe for human tissue so that it's not damaged due to the heat. That's what is used in medical devices as the safety limit: during use, the device must not heat the tissue temperature above 43 C. If the temperature of the skin does rise above 43 C then you can expect some damage, though I don't know how quickly it happens or how severe it is. Roger writes "we ran it for 18 minutes before getting a temp warning. The hottest part of the camera was the back behind the LCD door (43°C / 109°F)". So it seems that the 43 C tissue damage threshold is indeed what Canon used to design their overheating algorithm to protect primarily against, and they're running it pretty close.  (Canon also mention controls for internal temperatures as a secondary consideration in the CineD interview).
 
Of course, if you don't hold the camera in your hands during recording and use a tripod or gimbal, then it wouldn't cause burns. But they seem to have designed the protection for those in mind who do their videos hand-held. My guess is that the 43 C could actually be written into some countries legislation or regulations as well, so Canon might not have any choice about it. I'll try to find some information on this.

can confirm 1.1.1 works with date change and battery pull method to reset timer. 

Lensrentals Investigating the Canon R5 Heat Emission
https://wordpress.lensrentals.com/blog/2020/09/investigating-the-canon-r5-heat-emission/

How about we turn the camera on, do nothing with it, leave it in the menus.
Put it in the freezer.
After 1 hour, see if the timer has ticked down to 0 mins of 8K.
Who wants to see an OVERHEATED! SHUTTING DOWN! screen with frost on it?

The EOS R5 manual indicates that there is no separate battery for date and time storage. Probably just flash memory.

I may have overlooked it, but I haven't seen a message that the Canon EOS R5 gets very hot on the outside too.
Armando Ferreira says in his video 'The Canon EOS R5 IS NOT AN 8K CAMERA!': When the camera (R5) says it is overheated, I touch the camera, it is pretty much cool to the touch!
Does this not indicate badly calibrated heat sensors or an incorrect reading by the firmware? Or a combination of both?