There is an issue with the latest few BIOS update versions where the Windows BIOS update utility refuses to continue with the update (I forgot to write down the exact error).
I have found a workaround for this which I want to share. Since all the existing threads about this are locked because they are old I'm starting a new thread on this.
The workaround is to create a recovery flash USB drive in the utility instead of trying to have it apply the update directly; and then copy the L48_0148.bin file from the USB drive to the EFI\HP\BIOS\New directory on the EFI system partition of the tablet. After copying the file reboot into the BIOS (keep the volume down button pressed while rebooting and select BIOS setup) and leave the BIOS setup without making any changes, the BIOS update will start immediately after this.
This worked for me, hopefully it will work for others too.