Downgrade from Lightweight to Autonomous Using Linux

Hello world,

I recently came across a solution for a small problem I was working on, and I thought I would share.

I have a Cisco 1131 AG lightweight access point that I wanted to downgrade to autonomous mode. Now this is easy if you have a WLC (Wireless LAN Controller) that these APs are designed for, but if you don’t you have to perform a downgrade manually.

There are lots of instructions on the Internet, but this is the Cisco documentation for this issue.

What Cisco leaves out is what the AP is expecting out of your TFTP server. When the AP loads up into recovery mode it is going to be attempting to connect to a tftp server at the broadcast address: tftp:// — essentially this means that the AP will attempt to connect to an address that every device on the LAN has.

My laptop is running Ubuntu (a flavour of Linux) and I have the tftpd-hpa package as my TFTP server. Normally I like the setup I have, but today it wasn’t enough — the AP wasn’t connecting.

The CLI was throwing this error:


And when I used wireshark to look at the traffic I found that the tftp server wasn’t responding to the requests from the AP. So I configured tftpd-hpa to specifically listen on the broadcast address like this:


And restarted tftpd with /etc/init.d/tftpd-hpa.

Once I did that, the AP was able to connect and all was well in the world.


7 thoughts on “Downgrade from Lightweight to Autonomous Using Linux

  1. Hello world,
    I got to discover this site while searching online for solution to the present situation am going through. My case is a little bit different but similar. I just bought two aironet access point (1131AG) with autonomous IOS c1130-k9w7-mx.124-10b.JDA3 with a wireless lan controller. I am running win 7 64-bit.I need to convert one of the ap to lightweight to practice in my lab, I copied out the ios on it to a tftp server and the next day i power up the access point and it gave an error: ”The system is unable to boot automatically because there are no bootable files to boot”. and boots to ap: (rommon) with all LEDs red.

    I found on cisco community forum a step on how to load ios on an access point after the ios file had been erased or corrupted using a tftp server.

    I used the steps, using both the mode button and also using some commands. when I used the mode button, it started to extract the tar file from tftp with a broadcast address and when it had almost finished with the copying it gives the following errors:
    ”Premature end of tar file
    ERROR: Problem extracting files from archive.
    The system is unable to boot automatically because there
    are no bootable files to boot”.

    I tried to put those commands you used to configure the tftp server to listen on a broadcast address and it gave me ”permission denied”.

    I am using SolarWinds TFTP server on my machine. Could you please direct me to where to make these changes and how I can resolve the issue.

    Thank very much for your help.

  2. That narrows down my seach, thanks for the tip! Tftpserver for Mac OS X experiences the same problem.

  3. You sir, have made my day!

    I had the exact same setup (ubuntu + tftpd-hpa) and was able to get my AP back to autonomous mode thanks your sniffing 😉

  4. Thanks! I was able to use these instructions to downgrade a hand-me-down 1252.

    I have a mac. Tried to get tftpd-hpa working for mac (the mac TFTP Server app was not able to handle tftp requests sent to the broadcast address and was unsuccessful. So I had to run a VM with the most recent version of Ubuntu. I setup the network connection to bridge on my Ethernet connection–that is, after I ran a sudo apt-get tftp-hpa and got that configured like you suggested.

    My next big problem was that I directly connected an ethernet cable between the mac and the AP (LWAPP). Often times this connection would not work because each time I disconnected the AP from power, the interface would go down and parallels would take its time bringing the VM’s interface back up–usually missing the first and second tftp request from the AP.

    I also ran into an issue that I would get 95% of the way downloading the image and then it would error out and say “Premature end of file”–not like the premature end of file message that brought everyone here–I actually saw it downloading each file in the archive. It could have been a faulty connection, but to be sure I connected the mac and the AP to a switch to ensure I would not encounter any interface weirdness. Anyhow, connecting both to the switch did it–I now have successfully downgraded my firmware.

    Thanks again!

  5. Came across “Premature end of tar file” symptom while converting 3602i to Autonomous mode. Both Solar Winds and tftpd32/64 were causing timeouts during new image extraction process.
    Tried everything from “” method to config_recovery through broadcast with xxx-tar.default image but no dice.
    As a last act of desperation I’ve used one of available Cisco routers as tftp server – problem solved.
    It seems the root cause lies in an actual implementation of tftp client in APs ROM mode but I’m open to correction here.

  6. This suggestion saved me. I couldn’t understand why the tftp server on my ubuntu box was not responding to the request from the AP. Once I re-configured the tftp server as per your suggestions, I was able to recover my AP. Thanks for posting!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s