cannot uninstall linux-image-2.6.32-5-686

[David Zelinsky <dzpost@dedekind.net>]

I just did an 'apt-get dist-upgrade' from the lasted squeeze update, and
failed to notice it had decided to install a stock kernel image:
linux-image-2.6.32-5-686_2.6.32-48squeeze1.  I did not want this, since
I'm using a custom kernel, and I'm not sure the stock kernel will even
work.  Worse, the linux-image package did not install properly, with
some part of the post-install script returning errors (zz-update-grub).
The rest of the dist-upgrade appeared to succeed, but the
linux-image-2.6.32-5-686 package is in a half-installed state.

I tried removing the offending package ("apt-get remove") but got the
same error from the post-remove script.

How can I fix this?  I want the linux-image package to go away, and also
to make sure 'apt-get dist-upgrade' will not try to install it in the
future.

Here's relevant part of the output from apt-get dist-upgrade:

-----------------------
# apt-get dist-upgrade
[...]
Running update-initramfs.
update-initramfs: Generating /boot/initrd.img-2.6.32-5-686
Examining /etc/kernel/postinst.d.
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 2.6.32-5-686 /boot/vmlinuz-2.6.32-5-686
run-parts: executing /etc/kernel/postinst.d/zz-update-grub 2.6.32-5-686 /boot/vmlinuz-2.6.32-5-686
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
run-parts: /etc/kernel/postinst.d/zz-update-grub exited with return code 1
Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-2.6.32-5-686.postinst line 799, <STDIN> line 2.
dpkg: error processing linux-image-2.6.32-5-686 (--configure):
 subprocess installed post-installation script returned error exit status 2
[...]
Errors were encountered while processing:
 linux-image-2.6.32-5-686
E: Sub-process /usr/bin/dpkg returned an error code (1)
-----------------------

And here's what happened when I tried to remove it:

-----------------------
# apt-get remove linux-image-2.6.32-5-686
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  linux-image-2.6-686 linux-image-2.6.32-5-686
0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 79.9 MB disk space will be freed.
Do you want to continue [Y/n]? 
(Reading database ... 31079 files and directories currently installed.)
Removing linux-image-2.6-686 ...
Removing linux-image-2.6.32-5-686 ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 2.6.32-5-686 /boot/vmlinuz-2.6.32-5-686
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 2.6.32-5-686 /boot/vmlinuz-2.6.32-5-686
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
run-parts: /etc/kernel/postrm.d/zz-update-grub exited with return code 1
Failed to process /etc/kernel/postrm.d at /var/lib/dpkg/info/linux-image-2.6.32-5-686.postrm line 234, <STDIN> line 2.
dpkg: error processing linux-image-2.6.32-5-686 (--remove):
 subprocess installed post-removal script returned error exit status 2
configured to not write apport reports
                                      Errors were encountered while processing:
 linux-image-2.6.32-5-686
E: Sub-process /usr/bin/dpkg returned an error code (1)
-----------------------

Thanks in advance for any help.

-David