Installing Debian on USB

Question

From my Ubuntu, I want to create a bootable Debian USB. I tried to install Debian with debootstrap. A brief list of commands is

mount /dev/sdb1 /mnt
debootstrap sid /mnt http://ftp.debian.org/debian
chroot /mnt
apt-get install linux-headers-3.2.0-4-686-pae linux-image-3.2.0-4-686-pae
apt-get install grub2
grub-install --recheck /dev/sdb

I have edited the /mnt/etc/fstab to include the USB drive with its UUID. But my problem is installing grub from within chroot, I get the following error

/usr/sbin/grub-probe: error: cannot find a device for /boot/grub (is /dev mounted?).

I do not want to touch the grub of my ubuntu machine, I want to install the grub on my USB to be bootable on other machines.

What step/command I have missed?

Answer 1

You can bind mount pseudo filesystems such as /dev/ inside the chroot:

mount -o bind /dev /mnt/dev
mount -o bind /sys /mnt/sys
mount -t proc /proc /mnt/proc

Another option is to run grub-install from outside of the chroot, using --root-directory:

grub-install --root-directory=/mnt /dev/sdb