I am using the AES-Z7PZ-7Z015-SOM-G Rev C04. When the board is cold started (power up after being powered off for a while) it will boot into Pentalinux but will not load the OS from the eMMC. After a couple of power cycles it will eventually boot al the way up.
I put the SOM and Carrier in a temperature chamber and I could repeat the failure when the set point was less than 20C.
Below is a log of what I am seeing when it fails:
U-Boot 2015.07 (Sep 01 2016 - 14:31:20 -0500)