FreeBSD 9.1-RC3 not booting

[Thomas Krause]

Hi,
after upgrading Kernel from 9.1-RC2

# freebsd-update upgrade -r 9.1-RC3
# freebsd-update install
# shutdown -r now

the Kernel ist not booting. It just reboot's after the boot loader.
There no kernel.old. Safe mode also reboots.  What can I do to
recover the machine? (It was booting/running fine with 9.1-RC2)

Thanks for any help!

Regards,
Thomas.