Two Trees Sapphire pro 2 - exploring this corexy printer

[curious aardvark]

okay pid autotune total failure.
once it hits 20c past the set temp (tried several) it just says: temp too high, PiD failed.
So I think my next move is to try and flash it back to the factory original firmware.

That way if I still have the same issues - looks like I need a new board.
Which for around £30 Isn't a big issue.
Just a 2-3 week wait.

[AutoWiz]

okay pid autotune total failure.
once it hits 20c past the set temp (tried several) it just says: temp too high, PiD failed.

I am pretty sure this is your problem. In the configuration.h file with the heater settings there is a timer that the heater is expected to hold it's temp before the print starts and if your temps are not stable by more than 10c this might be your problem(there is also setting for how exact the temp has to be during this time). You need to calibrate your heaters. You can try tuning to a lower temp first. You can try changing the temp residency time to a lower number for that heater in Marlin. I think the default setting is 10(seconds) and I keep all mine set at 5 because I like my printer to print when I tell it to print. But you can lower it to 2 or even 1 so there is no delay and as soon as it crosses that temp it will start the pid autotune routine. And just put it back to 5 or 10 before you start printing just so the hot end has a good chance to heat soak at operating temp before it starts extruding filament.