I was looking at the schematic and noticed two things.

  1. They are using the TPS65217C PMIC
  2. The DDR3L is based on a 1.35 power source

Why are you not using the TPS65217D and applying the right power to the DDR3L?

  1. The TPS65217D came out after the initial design was done.

  2. The DDR3L can run at 1.5V without issue.

  3. The SW can set the voltage to 1.35V after power up.


Side note, while u-boot and the kernel support changing the pmic
voltage. We dropped this during 3.14.x or the 3.18.x cycle in the
default kernel device-tree, as there is no memory "checker" in
u-boot/kernel to verify the "contents" in memory where still "valid"
after the down-scaling. (i believe some random corruption was
actually seen on a am4x based board, so all am3x/am4x )

So if you do swap in the TPS65217D and want to run it at 1.35 to save
power, make sure you patch both u-boot and kernel. The voltage must
be set to 1.35 in u-boot SPL during ram init. (and patch the kernel
device tree to not set the 1.5v level)..