Bug#390401: Same problem, maybe fixed

[Jim Paris <jim@jtan.com>]

I ran into this problem on three installations now.  The fix I used
was to switch to a virtual console during installation and run

  chroot /target
  mount -t proc proc /proc
  DEBIAN_HAS_FRONTEND=1 /var/lib/dpkg/info/mdadm.postinst configure
    (press ENTER at each prompt)
  umount /proc
  exit

then go back to the installer and retry the grub setup (which was the
first step that actually stopped due to the mdadm being unconfigured).

Searching just now, I suspect this was already fixed recently:

 mdadm  (2.5.3.git200608202239-7) unstable; urgency=medium

   * Fixed a serious bug in the debconf script which would cause the
     configuration to exit prematurely in cases when the root could not be
     determined. Since this is RC, the urgency is set to medium.
   * Updated the documentation a bit.
   * Updated debconf translations:
     - Swedish by Daniel Nylander (closes: #389040).
     - Czech by Miroslav Kure (closes: #389083).
     - Russian by Yuri Kozlov (closes: #389086).
     - Brazilian Portuguese by Felipe Augusto.

 -- martin f. krafft <madduck@debian.org>  Fri, 29 Sep 2006 16:31:44 +0200

(As of when I did the installations, 2.5.3.git200608202239-6 was still
the version in etch).

-jim