If you have obtained a firmware folder (often named "sony reader"), users in community forums like MobileRead suggest this manual reinstallation process: Connect the PRS-300 to your computer via USB.
The Sony Reader PRS-300 (Pocket Edition) is a legacy device, and official software support from Sony has largely ended. However, you can still maintain the device through manual methods and community-driven tools.
: This open-source software is widely recommended for the PRS-300. It allows you to transfer books, manage your library, and convert file formats (like PDF to EPUB) specifically for the device's 5-inch screen.
Reconnect to the computer and delete the "sony reader" folder from the internal memory.
Since official software is discontinued, modern users typically rely on these alternatives to manage books and firmware:
: You can treat the device as a standard USB drive. Once connected, you can manually drag and drop compatible eBook files into the appropriate folders on the internal storage. Troubleshooting and Resets