How To Identify the Motherboard in your CR6 Printer - CR6Community/Marlin GitHub Wiki

How do I know if I have a Creality v4.5.2 or v4.5.3 or ERA1.1 motherboard?

You can open your printer - the motherboard version is printed on the face of the board, as highlighted in the pictures below.
IF you know that the motherboard in your printer was never replaced, then these guidelines may help you make a reasonable guess:
- If you have a CR-6 with a serial number before December 2020 (P202J*[month]*K[number]) you will have a v4.5.2 motherboard
- If your stock firmware was v1.0.3.7 or v1.0.2 you have a v4.5.2 motherboard
- If your stock firmware was v1.4.x or higher, you have a v4.5.3 or 1.1 ERA motherboard

And this is the BTT SKR CR6 motherboard, in case you have none of the above...

BTTskrCR6

No smoke - or at least, not due to the firmware.

However:

During homing the printer won't be able to read the optical sensor on the gantry, so it won't know when to listen to the strain gauge and may drive the nozzle into the print bed.
You will see a "Heaters Failed" warning if you try to heat the bed or nozzle, because Creality changed which pins they connect the heaters to, after 4.5.2, and Marlin notices if the temperature readings don't increase when it turns a heater on.
The part cooling fan will not respond to ON/OFF commands

pins_CREALITY_4.5.2.h reads:

pins_CREALITY_4.5.3.h reads: (same file apparently applies to the ERA board)