This is so short that is mainly a note to myself. On the other hand, I failed to find this on Google or StackOverflow, so here it is.
After installing Yosemite or El Capitan, your HFS partitions may get converted to some CoreStorage im-not-sure-what Volume. That won’t let Linux read those partitions. The solution is to boot OS X (recently renamed to macOS) and run:
diskutil coreStorage revert /
That will revert your partition to some im-not-sure-either state and Linux will be able to read it again.
Two things to note here:
- Right now, and for as long as I can remember, Linux can’t write reliably on HFS+ filesystems. Avoid writing them from Linux. Always mount them read-only.
- Fighting progress is futile. Installations and upgrades will probably keep converting your system to the new CoreStorage Volume thingy, whatever that is. Staying in the past is pointless, and I’m sure I’m missing some nice feature because I keep reverting my filesystem to the old format. All we can hope is that some day Linux will be able to access those partitions correctly.
To my expected readership of 1 (myself): hope you find this useful.