Multiple OS on SD card

[z4v4l]

* - neither Windows nor Android won't format an SD card with anything other than FAT and I think the same applies to iOS.

Rubbish - read the Android Adoptable Storage docs and you'll see that they require a filesystem with recommend ext4 or f2fs. SD manufacturers are fully aware of this - it's one of the reasons for them developing the application rating for their cards (A1 etc.)

do you distinguish between internal storage of a phone (eMMC, UFS) and removable storage (SD cards), right? I didn't check every android version released so far, what I have in my tablet, formatted a new SD card as FAT. and again - SD specification is clear about this, A1 rating has nothing to do with that requirement, that remains valid. they, SD Association, make a utility called SD Formatter, for people to format their cards properly. guess what, there is no choices for the FS, only FAT (appropriate version of it). I don't quite understand what's unclear in my statement about the requirement, the standardization body of the standard in question has made? you don't believe me? then ask SDA, sign NDA, get the full version of the spec and convince yourself on your own.