The general steps can be outlined as follows, but remember, these steps are generic, and you should consult specific guides for your model:

Before attempting a downgrade, you need to know the "Base Firmware" your console shipped with. If your base firmware is 4.89 or 4.90, you cannot go back to 4.88. Download the tool.

Place the PS3UPDAT.PUP file on a FAT32 formatted USB drive in the folder path: USB -> PS3 -> UPDATE .

Before attempting anything, check if your PS3 is even capable of running Custom Firmware (CFW). Downgrading is useless if your console model is incompatible.

The most famous method bypasses Sony entirely using a hardware flasher (like the E3 Flasher or a Teensy 2.0++). This device physically clips onto the NOR flash chip on the PS3’s motherboard.

Downgrading your PS3 firmware from 4.89 to 4.88 requires careful preparation and execution. While it's possible to downgrade, it's essential to understand the risks and consequences involved. If you're not comfortable with the process, it's recommended to stay on the latest firmware version.