[IDEA] Create/protect music partition on SD card

[Miss Sissy Princess]

I think the problem is that moOde does not handle the writing of the image in the first place.  The feature you need would need to be in the flash utility rather than moOde

Yes, that is why I wrote "It would be great if there was a "moOde installer" (MicroSD writer) application that would..."  

The simplest solution is to copy your music off before a major version and copy it back on afterwards,

What you're proposing would take hours and would subject an expensive 512GB MicroSDXC card to unnecessary write operations.  I made this suggestion specifically to avoid those issues.

But why would you copy it off?  If you're keeping your sole copy of your music library on a MicroSDXC card, hire an engineer to work with you to put together something more robust and resilient.  For example, I have the master copy of my music library on a RAID6 NAS powered by a 3000VA Eaton UPS.

which frankly I'd recommend even if the flash utility could handle partitions, just in case.

If you have doubts about the data integrity, you are much better off comparing the MicroSDXC copy of the music library to your master copy on your NAS.  It should be faster and it won't subject the flash memory to unnecessary write cycles.