Here are some steps on how to port U-Boot bootloader to a new, custom i.MX6 Linux board. Follow along to create a defconfig for your board.
SDRAM swapping rules for bit and byte swapping are not usually described clearly for slow SDR memories. Here are some rules for SDRAM chips.
i.MX6 DDR3 PCB layout can be a difficult task if you are new to routing DDR3 memory chips. Here are some notes on how to do it right.
Notes on how to build U-Boot from sources for a custom i.MX6 board. The notes assume that your custom board can use an existing defconfig.