The simple script is placed on your downgrading USB and when run (in Windows) it gives you options to load Lv2Diag.self files, FSM .PUP's, Recovery Mode .PUPs as well as the copy and management of bkpps3.bin files for clients.
The script also has md5 checking and other fail-safes.
This saves you the effort of copying/renaming all of the .PUP's and Lv2Diag.self's that you would be using in a typical downgrade setup.
Download Here