Consegui encontrar as instruções a seguir. Tendo feito isso sozinho no passado, posso confirmar que funciona.
On systems with Windows 8 pre-installed, you can access the UEFI (BIOS) setup screens from the Windows 8 boot menu:
- Press the Windows key + C, or swipe in from the right edge of the screen to open your Charms.
- Click Settings.
- Click Change PC Settings.
- In PC Settings, select General.
- Under Advanced startup, click Restart now. The system will restart and show the Windows 8 boot menu.
- In the boot menu, select Troubleshoot.
- In the Troubleshoot menu, select Advanced options.
- In the Advanced options menu, select UEFI Firmware Settings.
- Click Restart to restart the system and enter UEFI (BIOS).
ATENÇÃO:
Estas instruções aplicam-se apenas ao Windows 8.0