We believe that your issue has been closed by the upload of
Version 0.15 of grml-debootstrap from Michael Prokop <mika@grml.org>.
The explanation is attached below

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Format: 1.7
Date: Sun, 16 Dec 2007 16:30:37 +0100
Source: grml-debootstrap
Binary: grml-debootstrap
Architecture: source all
Version: 0.15
Distribution: unstable
Urgency: low
Maintainer: Michael Prokop <mika@grml.org>
Changed-By: Michael Prokop <mika@grml.org>
Description: 
 grml-debootstrap - wrapper around debootstrap for installing plain Debian via grml
Changes: 
 grml-debootstrap (0.15) unstable; urgency=low
 .
   * Make sure the passwd command succeeds.
     Thanks, Wolfgang Karall! [Closes: issue363]
Files: 
 57b4244943764b61abfe94b7e6949b28 682 grml optional grml-debootstrap_0.15.dsc
 2b5fea88e0693509c1113cdd2e43298d 44270 grml optional grml-debootstrap_0.15.tar.gz
 3daa21f1bda9d3357dad084493a08bb8 19086 grml optional grml-debootstrap_0.15_all.deb

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When misspelling the root password, the scripts ignores the error and no root
password gets set.

Something like the following should do the trick, feel free to issue some pretty
warning message inside the loop. :)

--- /etc/debootstrap/chroot-script.orig 2007-12-14 10:06:04.835720597 +0100
+++ /etc/debootstrap/chroot-script      2007-12-14 10:06:37.007592595 +0100
@@ -252,7 +252,7 @@ passwords() {
   else
      echo "Setting password for user root:"
      set +e # do not exit if passwd returns error due to missmatching passwords
-     passwd
+     until passwd; do :; done
      echo ""
      set -e # restore default behaviour again
   fi