Devo 12S and Deviation Fireware update question

Pertaining to the Devo 12S is this step necessary? This is on page 8 of the manual

Open the folder of the zip and copy all the files and directories inside this folder to the
root of the transmitter USB drive.

Yes,

Three steps.

1) upgrade dfu file

2) upgrade lib file

3) replace each file in the fs folder.

If you want to save your models, replace the new model folder with a copy of your old model folder.