Prostar Computer wrote:
You don't need to enable CSM to boot for a USB drive; you only need CSM to install a different operating system. Secure Boot = disabled is a must though. 🙂
Wouldn't say I'm an expert on this stuff, but with the ASUS notebooks at least, I seem to need to enable 'Launch CSM' as well as disable 'Secure boot' to boot to some things although honestly, I haven't tried disabling only secure boot that much, so others may want to check it out if necessary.
It may also matter how the USB boot drive was created.
If I understand this correctly, this
blog post mentions CSM allows you to boot to legacy or non-UEFI operating systems (or boot loaders/bootable DVDS?).
"Compatibility Support Module (CSM)
The UEFI boot manager is able to load legacy BIOS environment using the Compatibility Support Module (CSM). This module is able to emulate legacy BIOS environment and allow booting legacy operating systems or new operating systems which were installed without UEFI boot loader."
