I have the same problem now, not because of bios update, since my tablet is come with latest bios version.
I don't know if I have accidentally changed any battery power setting or bios settings.
Now the machine with shutdown or goes into hibernation mode and difficult to turn on.
The symptom is when the machine goes into sleep mode for a while, when I press the power button, it can't turn on, until I press the power button for example something near 20 seconds or long press for a number of times, then the machine can start up to the previous state.
My bios is 234, is that the problem with windows update?Or Bios settings?