Tuesday, 6 January 2009

Cisco 6506 recovery

Last night I did the bare metal recovery of a Cisco 6506 that we salvaged from an old company. I got two systems, one of them I had some trouble with, and ultimately wouldn't boot and complain about the backplane.

Trying to fix the problem, I accidentally deleted the good firmware image and the system wouldn't even boot anymore, stuck at the ROMMON prompt.

So to recovery a system from the ROMMON prompt, there's a quick way to work. Quick being a relative word, considering it still means easily half an hour to 40 minutes of work.

So, from there you just have to push a new image to memory using a serial cable. Needless to say, this is time consuming.

What I did was run the 'xmodem -cys 38400' command, put minicom from the 9600 speed to 38400, and fire away a new firmware image (CatOS 5-4-3 actually). The benefit of running xmodem with the -y and -s 38400 switches are increased speed as compared to standard xmodem (because you tell it to use the enhanced ymodem protocol) which would be forced to run at the standard console speed of 9600 for this type of system.

As an example, pushing the CatOS 5.4(3) image took roughly 30 minutes at 38400 bps. We'd be talking about easily 2 to 3 hours using 9600bps.

Once that was done, failed the first time because of bad CRC, redone, and redone a couple more times, I finally got it right: I was able to boot into a workable system, adjust configuration and download a good new image onto bootflash. Et voila, no more backplace issues, no more booting problems.

The next step will be to fix the attached MSFC1 to the SUP1A I currently have, which still refuses to boot. This is fairly straightforward, considering it's again getting into a ROMMON state, then downloading a new image for the MSFC1.

Thanks Cisco for this nice little ymodem feature, and the good documentation about recovery procedures. This was a cheap, but still really heavy and loud paperweight I had before I pushed a new configuration.

1 comment:

brad said...

Well done, Matt you accidentally solved a big problem of mine. Yes! I do have this same problem few days back and looking for the bit guidance which you have already provided in your post. I am Cisco Certification holder and it is my fourth renewing time I am preparing for the 642-845 , 640-822 and 646-204 exams by the way.