Hi here are the errors.
The pictures helped rule out a few things. It seems the update process is not able to recognize and/or copy the SYSTEM from the .update folder to the Flash partition. I will have to look into further this evening and see if anything has changed for the 7.9 version around how the squashfs is packaged (compression used, etc.).
Meanwhile, if you can get your system back working on the alpha 7.9 version via USB or SD (not NAND), one thing you can try is just drop the SYSTEM file from link below directly into the first partition (fat32 partition which mounts as /flash in libreelec - best to be accessed from Windows) and then try to boot libreelec. That will help eliminate some possible causes with the update package. Please use this SYSTEM (and not the one from the tar file): ?4l3cj8c9czvnkuk