Thanks, I'll give that a try. I used the renamer that downloads in the ZIP file and automatically renames it R4E.CAP (typo in my original message), and that is also shown in their table as below.
Rename the file as below table, and then save it to the USB storage device’s root directory.
Model name Rename the file
Rampage IV Extreme R4E.CAP
Rampage IV Formula R4F.CAP
Rampage IV GENE R4G.CAP