Trying out eMMC boot from our custom board (partly based on the Sabrelite desgin) and find that the board will not boot from the eMMC device (on USDHC2 port) with what I think is the correct settings with boot mode "10" for using external boot config settings. With the BT_CFG1_5 bit '1' which should be correct for eMMC boot, it will not boot, however if I set this bit to '0' for SD boot, it will boot. The boards also boots from a uSD card on USDHC4 port with this bit set to '0' as it should. Interface is 4 bit.
The eMMC device I use is a rev 4.41 device N2M400FDB311A3CE - Micron Technology, Inc.
Something obvious(?) I must have overlooked... u-boot is currently written to offset 0x400 of the eMMC