Lumia 1520 RM940 USA AT&T Downgrade issue
 

I have problem with this phone...on flight mode, phone software version is 8.1 and i want to downgrade it to 8.0, is it possible?

Hello. Yes, you can downgrade. Better use FW via phone product code and don't forget about Update NVI tick.

What's that ''FW'' ?

It is "Firmware" , in simple words - FFU image, which you can download in BEST > NaviManager tab.

Phone have flight mode issue on it coz of version 8.1, i search for the solution to fix this issue and that is downgrade to 8.0
So i flashed it first with this version 02540.00019 and second time with this version 02061.00074 with same Product code and all done good, but stay have same issue and same 8.1 version.
which version can i download from support to downgrade it in to 8.0 ?

Use any, but don't forget tick "Update NVI" button.

I tried with that but, it's still showing me that flight mode sign...i just want to know that which version have 8.0 from support area then i can download it.

Just any first in fw list will be the 8.0.