"ACU" firmware are ACTIONS firmware so you should try .bin or .fw both should work if all goes well.

What you should do is REMOVE all the funny characters in the filename as I think the program doesn't like it. Try just calling it "1" or something simple with no funny characters and see if the upgrade program works then.

ı try it like 1.fw and error say : read or write device information failed! please exit the program and check if device connecting!