The BootFriend installer can be repurposed to write any custom splash contained within a backup of the handheld's internal EEPROM. BootFriend functionality will not be installed in this mode. To achieve this:

1. Open the BootFriend configuration page: https://wonderful.asie.pl/ws/bootfriend/.
2. Select Custom Splash. Upload a 2048-byte file containing a backup of the internal EEPROM from which you wish to write the splash screen data.
3. Download the installer, and follow any other installation guide from that point onwards.