Solved! Go to Solution.
RESTORE DEAD KEYBOARD AND LEDS (ASUS GL703GS)
Two years later it started to happen again since the other day, right after hibernation or shutdown (no problem to resume from sleep)!!
Keyboard dead (no key works even from BIOS) and led is turned off, even power button is not backlit when this happens.
EDIT: used https://dlcdnets.asus.com/pub/ASUS/GamingNB/GM501GS/KBFWUpdateTool_v1.0.5_forSupportSite.zip
Just ran it from Windows 10 ("This tool will update your keyboard fw if needed... blah blah"), pressed the (only available) "Update" button... a progress bar started and after less then a minute the keyboard leds turned on during process and keys worked again! Didn't even have to reboot.
Checked hibernation and... it WORKS FINE AGAIN after resume! Lifesaver tool!
Everything runs fine, including numpad and caps-lock key led.
Let's just hope it works when it does again (in the next 2 years?) and will not complain that the FW is simply up to date at that time... (Yes, the tool worked fine after it happened again!)