Comment 78 for bug 1040557

On Sat, Dec 22, 2012 at 10:52:53AM -0000, montini wrote:
> Is there any information if it is safe to start 12.10 live USB flash in
> mode "UEFI and CMS" (mixed bootloader) on NP530U3C-A05EE? Or only the
> plain CMS is safe at the moment?

Only plain CMS is safe. Mixed bootloader options are specifically *not*
safe, because the live USB disk will be bootable under UEFI.

> I.e. is it only possible to dual boot ubuntu and win8 by switching boot
> mode in the BIOS settings or "UEFI and CMS" method is safe aswell?

Once you have Ubuntu installed in CMS mode, it will be safe to dual boot
because a UEFI boot loader will not be installed. But for first boot and
installation, you would need the machine to be in CMS mode only.

Also, if you are willing to help us test a fix for this issue, the following
would be useful. It does present some risk of bricking your laptop (if our
patch is wrong), so please only do this if you're willing to risk having to
RMA your machine!

 - put the BIOS in CMS mode
 - install Ubuntu to the internal hard drive
 - install Colin King's test kernel package from here:
 - put the BIOS back into "UEFI and CMS" mode
 - boot Ubuntu
 - verify that the samsung-laptop module still gives you access to your hot
 - configure your /etc/fstab to mount the EFI system partition (as used by
   Windows) at /boot/efi, and mount the partition
 - install the grub-efi package (note: this may require additional manual
   configuration to get it fully set up, I'm afraid I can't give very good
   instructions here)
 - reboot to Ubuntu using grub-efi, taking care to confirm that you're
   really booting the efi version of grub
 - verify that the samsung-laptop module does not brick your laptop

If you're not willing to risk your laptop on this test, that's perfectly
understandable. In that case, you should be fine to just install Ubuntu on
the machine in CMS mode.