Even I am facing the same issue. Not able to calibrate my DDR3L.
We are trying to load uboot usig imx_usb USB loader, but uboot failed to load.
We are able to boot half only and getting upto below consol message.
U-Boot 2014.07-08942-g515451c (Jan 02 2018 - 16:53:52)
CPU: Freescale i.MX6D rev1.5 at 792 MHz
Reset cause: POR
DRAM: 2 GiB
Kindly help us to solve this issue.