How to resign eboots 3.55 games to 4.21 CFW

Hi I have updated my PS3 to CFW 4.21, I have software to change the eboots to resign them to 4.21.

The question I have is that when I do this it give me a new eboot file (EBOOT.BIN.BAK) what do I do ?

(1) Rename the file to EBOOT.BIN and replace this with the original EBOOT file ?

(2) Add this file to the program with the EBOOT file

(3) delete the EBOOT file and replace it with this & keep the file name the same ( EBOOT.BIN.BAK)

:dontknow: