Configure Cisco AP in ROMMON mode (Recover from Corrupted Image)

I am going to configure this AP fully in rommon mode which will then be work fine after connected to the network without any configuration remotely. This can be handy when the OS is corrupted / accidentally deleted.

For any error which breaks the booting sequence / accidentally images deleted, the AP will directly go to the rommon mode like below. To go to ROMMON mode manually, you will need to push and hold the mode button while reapplying power for about 10 seconds until the LED turns steady red.

If you want to know how to factory reset a Cisco AP / delete all configurations, please refer this.

To view the contents in the flash, hit dir flash:/ command. If it is not working, you may have to initialize the flash 1st by entering the command flash_init. Type help to get help with commands.

I am going to reset the AP to factory defaults by restarting the power while holding the mode button.
When the LED on AP turns to red, release the mode button.

Default SET parameters are as follows.

Now you can see that the default router and the IP address are same. These are the IP addresses we use to upload the OS from a TFTP server (my laptop)



Change the default router address to 10.0.0.2 by entering the command :
set DEFAULT_ROUTER 10.0.0.2

Now setup your TFTP server. Im using TFTPd64 on my laptop. Connect the Ethernet port of the AP to the Ethernet port of the PC and give 10.0.0.2 with the correct subnet mask to the network interface of PC.

Copy the OS .tar file to the root directory of the TFTP server. The OS image I am using is ap3g2-rcvk9w8-tar.default.tar which is just a low end image which will only help the AP to communicate with the WLC.

Then it will be able to download the real image from the WLC. You will be able to upload the real image from this method too if you have it with you.





Now enter the command:
tar -xtract tftp://10.0.0.2/ap3g2-rcvk9w8-tar.default.tar flash: 

If the above command is not accepted, you will have to initialize tftp 1st..
tftp_init

(click on the image to view in full resolution)

Now enter the following commands

set IOS_STATIC_CONTROLLER_IP_ADDR 172.31.129.22 to set the WLC IP
set IOS_STATIC_DEFAULT_GATEWAY 172.31.129.126 to set the gateway of the VLAN
set IOS_STATIC_IP_ADDR 172.31.129.119 to set the operating IP address of the AP
set IOS_STATIC_NETMASK 255.255.255.192 to set the operating subnet mask

Now enter the set command to view all the set variables. It should be like this.

Now you can connect it to the network. If the switch is configured with the correct VLAN, everything will be fine.

Type boot and hit Enter..

Note that if the BOOT variable is not set, you have to set it manually first via the following command.

set BOOT flash:/FILE-NAME.tar

The AP will bootup with the recovery image --> find the WLC -->> download the complete image & register with the WLC.
You can then configure any other setting (secondary WLC, AP name etc) via remotely if necessary.

Note:-

to delete the flash with its folders enter the command: delete /recursive /force flash: in privilege mode. use with caution, it will delete all the files in flash with folders.