Customize alternate install CD with UEFI?

Josef Wolf jw at
Wed Jul 20 19:06:13 UTC 2016

On Wed, Jul 20, 2016 at 07:22:09PM +0200, Liam Proven wrote:
> On 20 July 2016 at 19:04, Josef Wolf <jw at> wrote:
> >
> > On Wed, Jul 20, 2016 at 03:57:56PM +0200, Liam Proven wrote:
> > The next question is, how to customize it? For the traditiona BIOS, I gave
> > isolinux the following line to start preseeding:
> >
> >   append  debian-installer/locale=de_DE.UTF-8 console-setup/ask_detect=false \
> >           keyboard-configuration/layoutcode=de \
> >           keyboard-configuration/variantcode=nodeadkeys \
> >           file=/cdrom/preseed/s-test.seed \
> >           initrd=/install/initrd.gz quiet DEBCONF_DEBUG=5 --
> >
> > How would I give this information to the EFI system? I see, efi.img is a
> > mountable image. But when I mount it, I can't find any configuration files on
> > it.
> I have no idea. I think you need to investigate what's inside it, what
> it's for, etc.. The filename extension suggests to me it's an image --
> i.e. a binary image of something, e.g. a block of memory. There's no
> guarantee it's a disk image.

Well, it IS a disk image. And those are the contents whenmounted:

  # file `find /mnt -type f`
  /mnt/efi/boot/bootx64.efi: PE32+ executable (EFI application) x86-64 (stripped to external PDB), for MS Windows
  /mnt/efi/boot/grubx64.efi: PE32+ executable (EFI application) x86-64 (stripped to external PDB), for MS Windows

> >> > While at it: the partitioner on ubuntu-16.04-server-amd64.iso don't seem to be
> >> > aware of the UEFI partitions?
> You need to tell us more about what the hardware you're using, what
> you want to achieve, size of disks, desired end result, etc. before we
> can comment on specifics.

This is an asus bu201la-dt022g notebook with win8.1 preinstalled. I upgaraded
to win10 and now I'd like to resize to install ubuntu.

The origial partitions are like this:

Disklabel-Type: gpt
part      start       end   sectors size   type
sda1:      2048    206847    204800 100.0m FAT32 ESP    (EFI system)
sda2:    206848    468991    262144 128.0m ----- MSR    (M$ reserved)
sda3:    468992 390236111 389767120 185.9g NTFS  Primär (C: M$ basic data)
sda4: 390236160 391174143    937984 458.0m M$ recovery environment
sda5: 391174144 924344319 533170176 254.2g MS basic data (D:)
sda6: 924344320 976773119  52428800  25.0g Win recovery environment

My goal is to free as much as possible for ubuntu, but still keep a "usable"
win10. I don't really need win, it's just for the case...

But my PRIMARY goal NOW is to create an EFI aware customized install disk with

> > BTW: When the EFI-installer starts, the partition /dev/sda (is this the EFI
> > partition) is already mounted and the installer complains that it is mounted.
> You must be *very* careful to use the right words.

Argh! the bad wording comes from the installer. It says:

  "the following drives have mounted partitions: /dev/sda"

The mounted partition is /dev/sda1, the EFI partition from the hard drive.

Josef Wolf
jw at

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