cannot install custom kernel 2.6.28.x series due to /lib/firmware

[graysky]

When I attempt to install a custom compiled kernel (2.6.28.X) from debs on my system, I get the following error:

dpkg: error processing linux-image-2.6.28.7-em64t_1_amd64.deb (--install):
trying to overwrite `/lib/firmware/atmsar11.fw', which is also in package linux-image-2.6.27.10-em64t
dpkg-deb: subprocess paste killed by signal (Broken pipe)


Here is the complete log:

$ sudo dpkg -i linux-image-2.6.28.7-em64t_1_amd64.deb 
[sudo] password for squishy: 
(Reading database ... 144190 files and directories currently installed.)
Unpacking linux-image-2.6.28.7-em64t (from linux-image-2.6.28.7-em64t_1_amd64.deb) ...
Done.
dpkg: error processing linux-image-2.6.28.7-em64t_1_amd64.deb (--install):
 trying to overwrite `/lib/firmware/atmsar11.fw', which is also in package linux-image-2.6.27.10-em64t
dpkg-deb: subprocess paste killed by signal (Broken pipe)
Running postrm hook script /sbin/update-grub.
Searching for GRUB installation directory ... found: /boot/grub
Searching for default file ... found: /boot/grub/default
Testing for an existing GRUB menu.lst file ... found: /boot/grub/menu.lst
Searching for splash image ... none found, skipping ...
Found kernel: /boot/vmlinuz-2.6.27.10-em64t
Found kernel: /boot/vmlinuz-2.6.27-11-generic
Found kernel: /boot/memtest86+.bin
Updating /boot/grub/menu.lst ... done

Errors were encountered while processing:
 linux-image-2.6.28.7-em64t_1_amd64.deb

I know that I can remove my current functional linux-image through dpkg and then I can install the new one, but I'd like to keep both on the system.

Here is the guide I have been using to compile a custom kernel on Intrepid.

There is also this related bug over at launchpad.

[dijetlo]

linux-image-2.6.28.7-em64t_1_amd64.deb

You have an AMD 64 bit processor?

[graysky]

No, that's just the name of the package... it's an X3360 (quad core xeon).