[Chilli] Backup the firmware of a Coova-Chilli custom-builded AP and upload to new AP of same brand

[KB Song]

Hello,

I am new to Open-Wrt, and please excuse me if I am in the wrong forum.
As stated in the subject, I would like to clone a custom-builded 
Open-Wrt AP, which is given to me by a oversea friend and I would like 
to make a clone of it, with the same brand AP unit.

Please advice is it possible to do that. If yes, appreciate you can show 
the step/procedure to do it.

Thank you very much.

KB Song