Things You'll Need
Instructions
Insert the USB flash drive into a USB port on the computer. Click "Start," followed by "Computer." Click the "Devices" link on the window that appears. Click the icon of the USB flash drive that is now seen. Drag any files and/or folders from inside the window, to the right of the icon, to the Recycle bin.
Right-click the icon of the Recycle bin. Select "Delete" from the pop-up menu. Click "Yes" on the confirmation window.
Download a PS3 firmware downgrader file to the desktop, such as the 3.55 Downgrade file. Double-click the file to decompress it to a folder, then double-click the folder to open its window. Double-click each of the two files inside the folder to decompress them.
Drag both files from inside the window onto the window of the USB flash drive. Do nothing until the "Copy" pop-up window has appeared and then disappeared from the screen.
Close the windows on the screen by clicking the "X" buttons on their upper-right corners. Shut down the computer. Remove the USB flash drive from the computer's USB port.