costasx sorry that you have trouble. I just dusted of and connected my Haswell NUC to my new setup and tested with LE SD/USB Creator and LibreELEC-Generic.x86_64-sky42-8.2.5-3.5-#181220.img.gz and it boots for me in Bios and UEFI mode.
For a update from 8.2.5-6.42.3 you dont need to boot from a USB stick. Just boot the LE and put a update tar file in the update folder and reboot. Take this libreelec-generic.x86_64-sky42-8.2.5-3.5-#190117.tar one (i will write the release post shortly).
This should work for you Update LibreELEC [LibreELEC.wiki]
Many many Thanks!!!!
Worked like a charm!!!
Great work sky42 Thank you very much!!!
So just to be sure... I'll be looking for the x86_64-sky42-x.x.x-3.5#xxxxxxx new versions for my hardware setup right???