Re: Re: installing from iso on partition to another partition, avoiding all access to usb

[Julian Rüger <jr98@gmx.net>]

Hello together,

it seems you are all thinking way too complicated. As I suggested in the
other thread, I'm just gonna post a little howto.

So, here it goes:

1. Booting from USB flash, USB hard drive, or internal hd, is basically
all the same. You first need to install grub2 on it. If you already have
a running system with grub2 on the hd you want to boot the installer
from, you can skip this step.

Let's assume your to-be install partition is /dev/sdb1 (file system
should not matter, can be fat32 on USB for example, or any fs linux
supports). You don't need to format this partition. For example mount it
as /media/install.

Install grub2 (as root) with:

# grub-install /dev/sdb --root-directory=/media/install

This will install grub into the MBR of sdb, which you will later use
your BIOS boot menu to boot from, and create a
folder /media/install/boot.

2. Now copy the .iso, or since there's this problem I encountered
(http://lists.debian.org/debian-user/2013/05/msg00291.html) it's easier
to unpack the contents of the iso to /media/install/debian_iso

3. Edit /media/install/boot/grub/grub.cfg and add the Debian installer
entry.

If you use your current system's grub, add it to the very bottom. (In
this case, any update-grub, i.e. from a kernel-update of your running
system will overwrite it again)

The entry should look like this:

menuentry "Debian 7.0 wheezy installer, x86_64" {
	linux /debian_iso/install.amd/vmlinuz priority=low vga=788 -- 
	initrd /debian_iso/install.amd/initrd.gz
}

4. Shutdown, press your BIOS boot-menu key (F10-F12 on most machines)
and select the disk that was /dev/sdb before.

The Debian installer should come up, you can select language, locale and
stuff and it should "fail to detect the CD-ROM" at some point.

5. Now Press Alt+F2 and Enter to get into Busybox's shell.

Mount your installer partition (careful, it might not be /dev/sdb1 any
more, check with ls /dev/sd*)

# mount /dev/sdb1 /mnt

Make sure it is the correct partition

# ls /mnt

If there is no debian_iso in there, try another partition.

6. Now bind (or symlink) the debian_iso folder to /cdrom:

# mount -o bind /mnt/debian_iso /cdrom

7. Press Alt+F1 to get back into the installer. Choose the step "Load
installer components from CD".

8. From here on, the installation should proceed normally.


I hope this helps! Have fun and good luck!

If you run into problems or have any more questions, reply to this
thread and CC me to make sure I notice.

Cheers,
Julian