The current software version is 3.6.10 and can be downloaded from the link below.
Additionally the "SD CARD CORE FILES" can be downloaded, extracted, and copied to a blank microSD card for replacing the MicroSD card in case of corruption.
Included are the stock Messages folder MP3 files, enet.cfg file, and the float control .bin and .info files.
Music track files would need to be copied separately.
See videos for removing and reinstalling the MicroSD card from the Unity Control box.
Removing the MicroSD card.
Reinstalling the MicroSD card.