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Some Linux Nerd
Asked: 2014-05-29 18:42:15 +0800 CST

Text on Cisco ASA console is garbled/missing letters

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I've actually looked up a number of solutions for this problem and none of them work. There's this Cisco ASA 5505 that I'd like to use, that outputs mildly garbled text with missing characters. I did some googling and found that the most likely problem is a bad baud rate, so I tried all the baud rates, 7N1, 8N2... basically every possibility minicom had. Then I figured (since I can type ok, just not read) that if I factory reset it that it would fix whatever is set wrong with the terminal. That didn't work either. This usb->db9 adapter and console cable work fine on the catalyst switch in our office. My serial settings are 9600 8N1 with no flow control. Anyone know how to fix this?

I have an example of the text on pastebin: http://pastebin.com/MAJF0mVU - it's just lots of "Dfaut cnfiuraionfil cotais 1enty." instead of "Default configuration blah blah"

cisco

1 Answers

  1. can't post comments, pardon the intrusion.

    you will most likely have to interrupt the bootloader (put it in ROMMON mode) and flash a new image.

    it could be nvram corruption (actually, that would seem to indicate a problem in flash).

    see: Cisco - Recover the Image on an ASA 5500 Series Security Appliance (PDF)

    or it could just be some control message is being misinterpreted. have you tried a telnet/ssh client? but that kinda looks doubtful.

    also, try different (lower) baud rates, could just be some settings on the unit, or erase nvram in rommon.

    edit: --

    well tbh, i've only dealt with asa devices on 2 occassions. so i just don't know enough about them to say.

    i couldn't make any sense of that log file, but looking at it now. it is failing to load the image, at the very end: eadng romflah.. !. rypochcksm (nchnge): f290c46b337a 5f275f 184120

    some checksum error

    normal output is !!!!!!!!!!!... spam.

    edit2 --

    just some more info on erasing flash: erasing/formatting flash should check for/mark bad blocks. additionally, erase marks blocks as 0xFF and reinitializes the filesystem. some of this stuff i just learned today, so bear with me ;p

    you can test the filesystem for bad blocks fsck -test flash. (these are bootloader commands) for a switch, the recovery looks something like format flash, flash_init, load_helper, copy image over, boot system flash:filename.

    as per the following guide: Recovering Catalyst Fixed Configuration Switches from a Corrupted or Missing Image

    bootloader cmd ref: Catalyst 2950 and 2955 Switch Boot Loader Commands

    image/filesystem ref: Managing Software Images and Working with Configuration Files on Catalyst Switches

    for asa 5500 series: ASA 8.x: Troubleshooting ASA Flash Errors

    closest i could get for ASA. i always have issues finding detailed guides for them, so i tend to use the switch/router guides as additional info.

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