“.PUP” files relate to the file extension used by the PlayStation 3 to update its firmware. If you have downloaded custom firmware, you can load that firmware onto your PlayStation 3 using a USB memory stick. Once connected to your PlayStation 3, you can choose to update the firmware from a portable storage medium. This will allow you to install your own custom firmware to your gaming console.
Click “Start,” then “My Computer,” then open the removable drive representing your USB memory stick.
Right click, then select “New Folder.” Name the folder “PS3.”
Open the newly created “PS3” folder, then right click and select “New Folder.”
Name the new folder “Update.”
Move the “PS3UPDAT.PUP” file into the “Update” folder.
Remove your USB memory stick from your computer and connect it to your PlayStation 3.
Turn on your PlayStation 3 and open “Settings,” then “System Update.”
Select “Install via Storage Device.”
Select your memory stick as the storage device. Your PlayStation 3 will now Install your “.PUP” file as its new updated firmware.