Re: How to get rid of M10
Le 09/08/2016 à 15:35, Mark Fletcher a écrit :
it isn't necessary to disable UEFI to get
Debian to install / boot.
Sometimes is it, due to unworkable UEFI firmware bugs. I've been hit by
a couple of them, notably graphic issues.
probably time to get used to UEFI, so as not to get a nasty shock at next
new machine purchase / build.
I second this.
The Debian install media can boot and/or install in UEFI or legacy BIOS
("MBR") mode.
BIOS, legacy or CSM mode. MBR is only the disk sector. EFI boot also
uses an MBR. It just does not use the BIOS boot loader inside.
1) UEFI boot works best (only?) with a GPT partition table.
Not only.
Compliant UEFI firmwares should boot equally well with MSDOS or GPT.
But, as I wrote, some firmwares are broken.
Windows requires GPT for EFI boot and MSDOS for legacy boot. Linux,
GRUB... don't.
there are gotchas to trying to use a GPT partition table with legacy boot.
Mostly due to BIOS firmware bugs. Again...
2) The partition table layout needs to be right for UEFI, and what works
for an MBR boot won't work for UEFI.
I'm not sure I understand what you mean.
Legacy and EFI boot have different requirements (legacy needs a boot
loader in the MBR, EFI needs a boot loader in the EFI system partition),
but they are not incompatible, so it is possible to have the same
installation boot either in legacy or EFI mode. When it's not possible
is only due to firmware bugs.
So you need to make the decision early in the process which boot method you
are going to use. The Debian installer can handle either, installing a
machine to boot MBR if it was booted MBR and installing to boot UEFI if it
was installed UEFI.
If the installer was booted in EFI mode it can also install to boot in
legacy mode if it detects another installed OS which boots in legacy mode.
What is extremely hard is booting a machine MBR and then setting it up to
boot UEFI.
I would not say "extremely", but harder than the other way around. One
reason is that you need to create an EFI system partition on the boot
disk, usually going through the hassle of reducing another partition.
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