We believe that your issue has been closed by the upload of
Version 0.9.2 of grml2usb from Michael Prokop <mika@grml.org>.
The explanation is attached below

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Format: 1.8
Date: Mon, 02 Mar 2009 16:40:55 +0100
Source: grml2usb
Binary: grml2usb
Architecture: source all
Version: 0.9.2
Distribution: unstable
Urgency: low
Maintainer: Michael Prokop <mika@grml.org>
Changed-By: Michael Prokop <mika@grml.org>
Description: 
 grml2usb   - install grml system / ISO to usb device
Changes: 
 grml2usb (0.9.2) unstable; urgency=low
 .
   * Rewrote grml2usb from scratch (in python). New features:
     - you no longer need to setup the device via /etc/fstab, just
       directly invoke "grml2usb /path/to/iso /dev/sdb1"
     - initial multi-iso / multi-boot support
       [Closes: issue501]  [Closes: issue584]
     - provide *several* new options like --bootloader-only,
       --bootoptions=... check out the manpage for all the details
     - get rid of "polution" of root directory on usb-pen
       [Closes: issue466]
     - always write a default MBR (thanks a lot to the work
       and help of Thorsten Glaser!) [Closes: issue295]
     - use grub by default (but support for syslinux is present as
       well of course)
     - fix regressions for temporary mountpoints / wrong directories
       [Closes: issue603] [Closes: issue602]
   * Update debian stuff:
     - Bump Standard Version to 3.8.0 (no further changes)
     - Change XS-Vcs-* to Vcs-* headers and replace mercurial with
       grml's nowadays git repository URLs
     - drop mtools from depends
     - slightly improve long description
     - add asciidoc, xsltproc and docbook-xsl to Build-Depends
     - either depend on syslinux | grub2 | grub
Checksums-Sha1: 
 2f6fdca79ceccf79f4976beb12c4199751c43db4 875 grml2usb_0.9.2.dsc
 85f814c2b9a17f6e111f8aaddc81cce5df46bae3 1211591 grml2usb_0.9.2.tar.gz
 70bc715d37aee6de650fdabbfaceece10e73b232 834794 grml2usb_0.9.2_all.deb
Checksums-Sha256: 
 bb98bde7d27e9d5ca88c585ed075a02b8d20a569659141726f64c34c00cf5cac 875 grml2usb_0.9.2.dsc
 0f32ab617d2c303cc1249b81fe75fea29d176e463ab493c4adbf397b244c0bea 1211591 grml2usb_0.9.2.tar.gz
 9ee3bb99149071f56684eb0671cc8eaa849fbf31f5c1bf681881b2b395a1a06d 834794 grml2usb_0.9.2_all.deb
Files: 
 ff4a02c1962af436a0c52bb444c55a18 875 grml optional grml2usb_0.9.2.dsc
 65f897b65934274163247b430cad7307 1211591 grml optional grml2usb_0.9.2.tar.gz
 a65bfb54fdd3a0c9d1a56c57cb90baed 834794 grml optional grml2usb_0.9.2_all.deb

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Would be nice to have a check for a valid MBR inside grml2usb and if no (valid) 
one is present display more information how to get one.

Thanks for the suggestion, Bernhard Tittelbach.