reboot does not work on origen ubuntu builds

I can reproduce the issue with 12.11 release at [1].

But if the replace the uImage and dtb with the latest tracking kernel based on 3.7-rc6, this issue does not come and system reboots perfectly. Below are the logs.

[1] http://releases.linaro.org/12.11/ubuntu/boards/origen/leb-origen-precise_ubuntu-desktop_20121127-494.img.gz

Logs
==================
root@linaro-ubuntu-desktop:~#
root@linaro-ubuntu-desktop:~#
root@linaro-ubuntu-desktop:~# reboot
root@linaro-ubuntu-desktop:~#
Broadcast message from root@linaro-ubuntu-desktop
        (/dev/ttySAC2) at 0:01 ...

The system is going down for reboot NOW!
Checking for running unattended-upgrades:
speech-dispatcher disabled; edit /etc/default/speech-dispatcher
[ OK ]ing all remaining processes to terminate...
[fail]ling all remaining processes...
modem-manager[1693]: <info> Caught signal 15, shutting down...

[ OK ]onfiguring network interfaces...
[ OK ]ctivating swap...
[ OK ]ounting local filesystems...
umount: /run/lock: not mounted
 * Will now restart
[ 125.165000] Rest

U-Boot 2012.07 (Nov 22 2012 - 00:50:09) for ORIGEN

CPU: Exynos4210@1000MHz

Board: ORIGEN
DRAM: 1 GiB
WARNING: Caches not enabled
MMC: SAMSUNG SD/MMC: 0
In: serial
Out: serial
Err: serial
Hit any key to stop autoboot: 0
reading uImage

3911864 bytes read
reading uInitrd

3807675 bytes read
reading board.dtb

16717 bytes read
## Booting kernel from Legacy Image at 40007000 ...
   Image Name: Linux-3.7.0-rc6+
   Image Type: ARM Linux Kernel Image (uncompressed)
   Data Size: 3911800 Bytes = 3.7 MiB
   Load Address: 40008000
   Entry Point: 40008000
   Verifying Checksum ... OK

Now reboot works well on Samsung Oriegn board with Linux Linaro ubuntu Quantal image:

http://snapshots.linaro.org/quantal/pre-built/origen/41/origen-quantal_developer_20130107-41.img.gz