How to Flash OpenWRT on Cisco Meraki

If you have a Cisco Meraki AP with an expired cloud license, its pretty much useless. However, if you have a RaspberryPi, some wires, and some patience you can pretty easily Flash OpenWRT on Cisco Meraki.

Disclaimer : This voids your warranty and Meraki subscription so best done on decommissioned units that have not been updated in awhile. May not work on new units.

Things You’ll Need

  1. Cisco Meraki MR33 AP (can be done on other models with serial pins)
  2. RaspberryPi with GPIO Board + Monitor + Keyboard + Mouse
  3. Three Pin-To-Pin jumper wires (can be salvaged from old IDE cables)
  4. Ethernet Cable
  5. Torx Screwdriver and a pry tool
  6. A Laptop and this Google Drive Link (contains the files we need)

Flash OpenWRT on Cisco Meraki

First, remove the 4 screws (behind the rubber stoppers) on the grey underside of the AP, then pry it apart at the seams.

Step 1 : There are 4 screws behind the rubber ‘feet’ on the grey side of the AP. Undo them, then pop the AP apart by using a plastic or metal knife.

Step 2 : On your RaspberryPi download all of the files in the Google Drive. Extract them with a ZIP tool, then put them in a folder.

Step 3 : Enable Serial GPIO on the RaspberryPi by typing “raspi-config’ navigating to Interfaces -> Serial -> Prompt 1 Hit NO -> Prompt 2 Hit YES-> You will see a confirmation , hit OK -> Hit Finish (bottom right)

This will enable the Serial on the GPIO pins which run across the side of the raspberrypi , to figure out your serial interface d0 the following command :

Take note that we will use the ttyS0 interface

Step 4 : Connect these GPIO serial pins on the RaspberryPi to 3 pins on the Meraki board.

D0 NOT connect anything to the pin with the white arrow on it.

Step 5 : Now Launch the flashing script with the following command , you need to add the name of your serial interface with the –serial={interface path}. After the python script is running and you see “Uploading image” then power on your AP to boot it , be careful not to let the serial wires move or shift.

If done correctly you should pretty instantly see the following output after booting the AP :

Wait a couple minutes for it to finish. If this fails, your AP may be on newer firmware which prevents this.

Step 6 : One the upload is done. Connect an Ethernet cord to your AP from a laptop or the Pi , set your interface IP to 192.168.1.2 and your gateway to 192.168.1.1 with a subnet mask of 255.255.255.0 and verify it works by pinging 192.168.1.1 , if you get a response port 21 should also be open.

Now Upload OpenWRT to the AP via TFTPD64 by hitting the PUT button :

The AP should now Reboot after this is uploaded, wait till pings return, now you can browse to http://192.168.1.1 and see the following or SSH to see OpenWRT!

Login is root no password, do set a password once you login 🙂

Now use WinSCP to connect to the AP via SSH and transfer the .bin file to the AP

Finally , You can reboot the AP to go back to Meraki or run this command which will install OpenWRT permanently 🙂

This concludes how to flash OpenWRT on Cisco Meraki ! For more Tech articles click here.