I could't see which hashboard detect over temp would you mind to try to run the miner with one hashboard? I mean test them one by one disconnect the two hashboard power and data cable and test again to find what hashboard is broken.
Also, try to hard reset the unit by holding the IP report button for 5 seconds or more then release then test it again and check for changes.
Thank you for your post! I had the same issue (ERROR_TEMP_TOO_HIGH) without knowing where it was coming from. This was a great suggestion, and after trying other fixes like replacing the PSU and cleaning everything, following your suggestion (one by one attachment of each hashboard) isolated the problem.
Thanks again!