XPS 13 (9343) A01 not recognizing Plextor SSD

I bought a 9343 recently and was hoping to use the A01 firmware for better Linux compatibility. I'm using a Plextor PX-G256M6e (M.2 PCI-e x2) SSD in place of my Samsung PM851 128GB that came with my XPS.

Using the A00 firmware, the drive boots normally. It loads the Dell logo, then the Plextor firmware logo, then continues to boot as normal (either F2/F12 or through to the EFI). After installing A01, the drive doesn't boot. It goes to the Dell logo and goes to a black screen after that -- without the Plextor firmware. Sometime after, the fan turns on at max speed.

The Samsung PM851 drive works properly with A01 so I suspect something is happening with the A01 and my Plextor SSD. Reverting back to A00 allows me to use the Plextor SSD.