08-27-2013 01:14 AM
Welcome to Lenovo Community Forums!
I’m glad to inform you that BIOS Update is not required for G580 (20157) model and it is not available online as it is not required.
Do post us back for further queries.
11-16-2013 10:54 PM
11-17-2013 12:29 AM
repeatedly press F2 when u start your laptop to go to bios setting.
In the boot tab change boot mode to legacy support.
and u will be able to boot from the os u were having on ur laptop.