On Tue, Aug 9, 2016 at 8:02 AM Karol Augustin <ka...@augustin.pl> wrote:

> On 2016-08-08 23:12, Maureen L Thomas wrote:
> > I have an acer aspire XC-704G with windows 10 on it.  I changed the
> > BIOS to boot from CD/DVD but all I get is a message to put a boot
> > device in and reboot.  It will not recognize the bootable DVD with
> > Debian on it.  What else do I need to do to get rid of 10 and put
> > Debian on it?  Thanks for your help
> >
> > Maureen
>
> What I always recommend is to disable UEFI in BIOS. The option you're
> looking for is LEGACY BOOT/UEFI switch. Then you'll be able to set boot
> order normally and install OS. I've heard that Linux supports UEFI but
> it was always really painful for me to get it working. If you plan to
> use Linux exclusively than LEGACY BOOT might be the easiest way to go.
>
> Karol
>
>
> I'm not sure I can agree with this. By all means disable "secure boot",
that you will have to do, but it isn't necessary to disable UEFI to get
Debian to install / boot. UEFI is what all new machines support and legacy
boot modes are starting to disappear from modern motherboards (by no means
gone, but the trend isn't in a good direction for BIOS dinosaurs). So it's
probably time to get used to UEFI, so as not to get a nasty shock at next
new machine purchase / build.

The Debian install media can boot and/or install in UEFI or legacy BIOS
("MBR") mode. The choice has several implications:

1) UEFI boot works best (only?) with a GPT partition table. Legacy boot can
be done from either but is easier with an old "DOS" partition table --
there are gotchas to trying to use a GPT partition table with legacy boot.
I forget the details but I wrestled with this earlier this year when
installing my first UEFI system (which was LFS, so I had to set up
everything myself).
2) The partition table layout needs to be right for UEFI, and what works
for an MBR boot won't work for UEFI.
3) BIOS settings needed for UEFI are totally different than what we all
worked with for years. Recognise that change is the only constant, RTFM,
and get used to it. (and don't do what I did and STFM [Skim the...] because
then you will eff up your partition structure and that would have been
painful if my machine's SSD had been bigger than 32G...)

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.

What is extremely hard is booting a machine MBR and then setting it up to
boot UEFI. With the aforementioned LFS system I ended up plugging in 2 USB
keys, one blank and one with the Debian installer on it, installing Debian
onto the blank key, then booting that to get an environment from which I
could set up UEFI boot for my LFS box to boot UEFI from its own SSD. That
worked because the Debian installer can handle both MBR and UEFI
environments. Using the Debian installer to actually install Debian, you
dodge that.

One note, although the Debian _installer_ can handle UEFI boot, at last
check the Debian _LiveCD_ is MBR only. I have no idea why. But you don't
see me doing anything about it, so the volume you will hear me complaining
about it is correspondingly limited :)

Mark

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