I'm missing documentation regarding booting from u-boot simply from RAM. The official i.MX Linux User's guide only tells one how to flash SD/eMMC etc.
Use case: quick test runs, besides the NFS-boot use case.
Our Linux build does not support such boot.
As for u-boot itself it is able to boot something from the RAM.
I mean it has commands like fatload or ext4load to load the binary to the RAM and bootm one to run it.