We believe that your issue has been closed by the upload of
Version 1.1.16 of grml-etc from Michael Prokop <mika@grml.org>.
The explanation is attached below

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Format: 1.8
Date: Mon, 01 Jun 2009 19:46:56 +0200
Source: grml-etc
Binary: grml-etc
Architecture: source all
Version: 1.1.16
Distribution: unstable
Urgency: low
Maintainer: Michael Prokop <mika@grml.org>
Changed-By: Michael Prokop <mika@grml.org>
Description: 
 grml-etc   - ecetera files for the grml system
Changes: 
 grml-etc (1.1.16) unstable; urgency=low
 .
   * /etc/init.d/grml-reboot: apply patch by Andreas Thienemann
     to put "/etc/init.d/$command" into RAM as well so poweroff
     works as expected when booting via PXE. [Closes: issue677]
Checksums-Sha1: 
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 307a7bfffbbe6ca6af8edfd7d9722a504d435ccb 156241 grml-etc_1.1.16.tar.gz
 20f83abd1390e2ae5be1f0c86c988820e25358b2 158714 grml-etc_1.1.16_all.deb
Checksums-Sha256: 
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 10de540acdd67d955a204691986a4bdda0e87255ceb8acde492357e3a5d62431 156241 grml-etc_1.1.16.tar.gz
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Files: 
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 ce191e73231d2a7d2ce29a5119897ecf 156241 grml optional grml-etc_1.1.16.tar.gz
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Bugreport and fix by Andreas Thienemann:

When booting via PXE and using 'poweroff' the system isn't halted.