Comment 8 for bug 1579609

Worth mentioning in my particular case (#7 above), the /dev/sd[a-z]9 partition has its type set to "Solaris reserved 1" so it should not even be probed really. Appears os-prober isn't actually looking at the partition type flags, or at least isn't blacklisting flags that shouldn't be probed.

# fdisk -l /dev/sdy
Disk /dev/sdy: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 03FE731F-E79A-A243-B9B3-AD9F480A5494

Device Start End Sectors Size Type
/dev/sdy1 2048 5860515839 5860513792 2.7T Solaris /usr & Apple ZFS
/dev/sdy9 5860515840 5860532223 16384 8M Solaris reserved 1