I updated my U330 to Windows 8.1. The process appeared to go smoothly, but I now have another new issue.
If I close the lid, it goes to sleep. When I re-open the lid, the sytem does not wake up automatically. Pressing power button does nothing as well.
All I can do is a hard shutdown (pressing the power button for longer time) and reboot. This occasionally gives an error message on restart, but has not produced any absolute solutions to the wake up issue.
Re-instaling new and older drivers do not solve the problem.
A new BIOS should fix this.
Please check the download link below to the get the BIOS.