A customer bricked an HP HDX 16 during a BIOS update. The problem was caused by PEBCAK, the customer disconnected the power cord. Usually there is a procedure to reload the bios from a bricked motherboard. I started googling around. The search was usefull as I resolved the problem and now the BIOS is flashed and the OS boots.
The Good news:
If the notebook beeps it is still alive and you can bring it back to life.
After the notebook is powered on, the white LEDs switches on but the screen remains blank. Caps Lock and Block Num blinks. The notebook beeps.
Go to the hp support site and download HDX 16's BIOS update. Run the executable file and it will decompress in a folder like"C:\SwSetup\sp46073". There will be a file called "3610F32.fd". That file must be copied to a formatted usb flash drive (FAT16 or FAT32) and renamed with the following names:
(I'm not sure which file name is correct, but it was one of the list as the process worked)
The name of the files can be read from the platform.ini file in the decompressed folder in the following section:
The next steps:
Disconnect the battery and the AC Cord,
Press and hold WIN + B keys
Connect the AC Cord, wait 5s and switch on the notebook
After 15 seconds release the WIN + B keys.
The beeping of the computer should be different and the led of the usb flash drive sould be blinkng.
Wait until the notebook powers itself down.
Disconnect the AC Cord and wait a bit, reconnect the cord and power on the notebook. All should be working fine now.
I had to retry a couple of times to get the procedure to work.