The root cause of the issue is 8.5 and later versions need to use c3700 / cx700 to join ME. If your AP version is lower than 8.5 you need to upgrade to ap3g2 and then upgrade to c3700.
After that, you can successfully join the WLC.
For my TFTP server I am using a Synology NAS and running the TFTP Service:
How to setup Synology NAS TFTP
Cisco AP Process
Power the AP off and hold down the mode button.
While the mode button is pressed down hold it and power the AP back on.
Continue to hold the mode button down until the AP’s light goes solid red.
Once the AP is red lit, let go and console into the AP using your console cable.
set IP_ADDR <DEVICE IP ADDRESS>
set NETMASK <SUBNET>
set DEFAULT_GATEWAY <GATEWAY IP>
tar -xtract tftp://<TFTP SERVER IP>/<.TAR FILE> flash:
set BOOT flash:/<.TAR FILE>
set IP_ADDR 10.0.30.53
set NETMASK 255.255.255.0
set DEFAULT_ROUTER 10.0.30.1
tar -xtract tftp://10.0.30.14/ap3g2-rcvk9w8-tar.153-3.JF10.tar flash:
set BOOT flash:/ap3g2-rcvk9w8-mx
My TFTP server is 10.0.30.14
The subnet is a /24
The gateway is 10.0.30.1
initialize tftp, ether and flash services on the AP
Extract the tar file in the TFTP servers root directory (the file is named ap3g2-rcvk9w8-tar.153-3.JF10.tar ) and we are extracting the file into our flash directory.
***DURING THE TAR EXTRACT PROCESS CONTINUE TO HIT SPACE BAR EVERY 1 – 2 SECONDS*** if not than you can receive a premature error.
Set the boot file location and let the AP sit for 5 minutes after finished booting new image you should be able to see it on the WLC and it will be in a Registered State.
WLC GUI – AFTERMATH
Now we can update the AP name, location, set a static IP for the device.
Hardcode the controllers.
The Access Point has now been successfully upgraded and is now registered to the Virutal wireless LAN controller.