Activating CAN0 bus on BBB looses HDMI video

Hello all,
I have been working on to get onboard CAN0 bus of BBB up and running using ubuntu 12.04 kernel 3.8 bone 20
I followed the web site that was given here before which is the following link

http://www.aero-box.co.uk/beaglebone-black#TOC-Enable-CANbus-device

I followed the instructions and modify device tree and compile it, load it to /boot/dtbs folder,
I use hdmi connection to SAMSUNG LN32D403 LCD tv and usb hub to connect mouse and keyboard.

But as soon as I reboot with modified am335x-boneblack.dtb file, I lost hdmi video, then I ssh’ed to the BBB to see what is going on
I saw CAN bus enabled but when I try to see what hardware resources loads in /sys/devices/bone_capemgr.*/slots,
I dont see anything loaded even 2GBeMMC, is this a pinmuxing problem that I am not aware off or kernel/firmware problem?

Any help or information greatly appreciated.

Thanks

To follow up on that,
I downloaded Robert C. Nelson latest kernel bone21.2 and modified device tree file to enable CAN0 and CAN1 buses,
compiled the kernel, reboot with the new kernel, now I have HDMI video as well as CAN network altogether…
I use 13.04 ubuntu rootfs and kernel 3.8.13.bone21.2 for that, but when I boot BBB, it falls into 1920x1080@24Hz graphic mode
I changed the KMS in uEnv.txt to change 1280x720@60Hz it is fine in text mode, but as soon as I start X server, it reverts back to
1920x1080@24Hz mode, some time later it freezes (had to hard reset BBB).
I looked at EDID information with parse-edid command, it does not even show 1920x1080@24Hz mode there…
Here is the EDID information.