mount-sd@.service does not (really) unmount
Dear sailors,
the instanciated systemd unit mount-sd@.service does not really and not cleanly unmount partitions on SD card it has mounted since its introduction in official SailfishOS releases (i.e., v2.2.0 in June 2018), potentially resulting in data loss on shutdown or reboot of SailfishOS.
For a detailed and technical description of this issue, plus a working and tested solution, see mer-core:udisks2 MR !24.
In short: AFAICS, the "-" only prevents the non-functional unmount command from blocking the shutdown of SailfishOS.
Workaround: Install mount-sdcard.
P.S.: See also udisks2 issue #1 at git.sailfishos.org/mer-core/
HTH & good sailing