Asus ExperBook B1500 stuck at firmware update screen after drained battery

[Lars-Erik]

When I booted my Asus ExpertBook B1500 laptop yesterday it presented me with this message: 

"power problem, check battery is connected and charged to at least 20%"

Don't know why this problem occured, but charged the laptop for some hours.

When I now boot it it just goes to a screen with the text:

"PD Firmware update. Progress Update. ERROR: erase timeout 1"

Then the screen goes blank (but backlight stays on).

What has happend?  How do I fix this?

I can't access BIOS, and can't boot from external USB either :-(

 

[Lars-Erik]

Short update. If I keep pressing "ESC" or "F2" while powering on I get an "Enter password" box (to enter the password for BIOS to go to "boot menu" (ESC) or "BIOS setup" (F2). But the ketboard does not work, so I can't enter the password or anything. So still stuck. If I uplug the PSU and try to boot I get a "Warning" box about "power error" with a mouse pointer and an "OK" button. But the mousepad does not work. Neither does an external mouse. And I can't click "OK" by pressing the "Enter" key either. Nothing seems to work 😞