Well, 10.2.1MP3 bricked my MBPr (and a 2012 Air) running 10.7.4. 10.2.1MP3 is supposed to support this architecture!
I installed PGP, rebooted, and encrypted without errors.
The next time I rebooted however, the passphrase screen comes up, (twice) and I enter the passphrase (twice) then I get NO ENTRY.
I booted into thunderbolt target disk mode and decrypted from another machine.
Both laptops are STILL bricks.
Neither will boot anything, even bootable USB drives. This is bad, real bad.