We need to upgrade cisco 1200 with ISO version 12.3 to LWAPP, i have downloaded the LightweightMode Upgrade Tool and the upgrade image , i suppose the upgrade will happen with the help of controller can you please guide.(we dont have the controller at present)
Here are two good related docs;
Upgrading Autonomous Cisco Aironet Access Points to Lightweight Mode
LWAPP Upgrade Tool Troubleshoot Tips
Hope this helps!