Initially not powering on - tried all recommendations per https://www.asus.com/support/FAQ/1014276.
Despite battery charge being around 90% per last night, and the laptop was shut down properly (not sleep mode).
Black screen, no indication of screen being powered (no backlight), no external screen via HDMI.
After a while trying to power it up, trying to enter BIOS (via F2, unsuccessful), the white Power light came on, and the Batt light started flashing white 2x, then short pause, then 2x again. See attached video.
Any suggestions what this error code may mean?
Any further troubleshooting recommendations?