Why does my USB hub hide a directly attached drive from the boot menu? (post-Filevault) I recently enabled FileVault on both my mid-2012 Retina MacBook Pro and my external USB drive containing a Carbon Copy Cloner backup.

My external drive is attached directly to the MBP. I also have a powered USB hub attached to the MBP's other USB port (no drives are attached to the hub).

Since enabling FileVault, I've noticed a peculiar behavior on the boot menu (holding option at startup):


If I leave the hub attached during startup, the CCC drive doesn't show up in the boot menu.
If I leave the hub unplugged during startup, the CCC drive shows up.
Swapping the USB ports for the drive and hub changes nothing.


Any ideas what the cause of this might be?

(Side note: I've also noticed that both the internal recovery partition and CCC's recovery partition are missing from the menu. But that's apparently normal from what I've researched.)
Its because the hub is able to connect drives so the hub shows it similar to how an empty optical drive shows up.