u-boot/kernel in eMMC, rootfs on SD

newbe question:

I’d like to have u-boot and kernel resided in on-board flash, but rootfs on the SD card

perfect solution would be everything in flash, but /home mounted from SD card.
but for now (when LCD7 driver conflicts with eMMC driver for BBB and does not allow rootfs to be loaded when LCD7 cape is connected to BBB), I’d be happy even if entire rootfs is loaded from SD.

Any pointers?

PS: I may be asking trivial questions. Sorry (newbie is here). When I google my question, I get a bunch of non-related links. May be I’m asking my question wrong (in google).