1. Download the Firmware:
- Visit muos-s.dev.
- Navigate to the "Release 35XX Plus" section and download the "2405 beans" zip file.
2. Prepare the SD Card:
- Extract the zip file to get the image file.
- Use Balena Etcher or Win32 Disk Imager to burn the image to your SD card (64GB recommended).
3. Initial Setup on Device:
- Insert the SD card into the RG35XXSP and power it on.
- Select "Plus" as the device type, set your time zone, and configure the date and time.
4. Configure SD Card Partitions:
- Connect the SD card to your computer.
- Assign a drive letter to the ROMs partition using Disk Management.
5. Add ROMs and BIOS:
- Download and organize your ROMs by system (e.g., NES, SNES).
- Copy the ROMs to the appropriate folders on the SD card.
- Obtain BIOS files and place them in the BIOS folder on the SD card.
6. Install Additional Features:
- For cheats, download the RetroArch database and place it in the cheats folder on the SD card.
- Download themes and drastic configuration files from the MUOS Discord and place them in the corresponding folders.
7. Add Box Art:
- Use a program like Scraper or download pre-packaged artwork from the MUOS website.
- Copy the images to the artwork folders on the SD card.
8. Final Steps:
- Insert the SD card back into the handheld device.
- Connect to Wi-Fi and adjust settings as needed.
- Customize RetroArch shortcuts and themes through the applications menu.
9. Enjoy Your Customized Device:
- Explore games, apps, and new themes.
- Install and configure ports for additional games.
With these steps, your RG35XXSP will be running custom firmware, providing enhanced functionality and a personalized gaming experience. For detailed instructions, visit muos-s.dev.