Last week I updated my NUC6CAYH BIOS to 0045, coming from 0041. A while later, I discovered that CEC (Wake on TV) stopped working, so I downgraded to 0041 with the IFlash utility. Flashing procedure went normal and the system rebooted. After the reboot the system became unresponsive. No activity on USB, HDMI or VGA connections, only Power Button LED lit.
I have tried every imaginable (recovery) solution to revive the system, of which none worked.
After some reading up, I discovered that a downgrade from 0045 to 0041 should not be possible, due to a security enhancement. It seems a message like "Incompatible BIOS Version, Update aborted..." should have aborted the flashing procedure, which it didn't.
I'm curious to know what exactly went wrong. The system clearly ended up in a state from which recovery isn't possible. I have sent the NUC back to the supplier for repair.
Thank you very much for sharing your issue with the Intel® Communities Team.
I understand that you are facing some issues with you NUC after a BIOS downgrade which will not turn on anymore.
It seems that something went wrong whit during the BIOS downgrade process. I am not able to determine what exactly went wrong since I was unable to see the downgrade process nonetheless, if the NUC is not booting up it might be an error during the downgrade.
I can see that you already sent this unit for repair. In the case that the problem is not fixed, do not hesitate to https://www.intel.com/content/www/us/en/support/contact-support.html contact us to verify your preferred replacement method if the product is under its warranty period.
Antony, thanks for responding.
I have received my replacement NUC, and luckily it came with BIOS 0041, so my CEC (Wake on TV) problem is "fixed". Of course, I'm now reluctant to update to 0047. Is it better to open a separate thread regarding my CEC (Wake on TV) bug, or just continue here?
Thank you very much for sharing that information and is really good to hear you have your replacement now.
For your CEC issue, I will recommend you to open a new thread so we can provide you further assistance. Make sure you describe your problem and provide your system details on it.