I followed https://www.nxp.com/docs/en/user-guide/i.MX_Yocto_Project_User%27s_Guide_Linux.pdf but used the imx-4.19.35-1.0.0 release and when I boot my board all I see is:
U-Boot SPL 2019.04-imx_v2019.04_4.19.35_1.0.0+g85bdcc7981 (Sep 15 2019 - 22:50:28 +0000)
DDRINFO: start DRAM init
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
Steps I took to build image:
repo init -u https://source.codeaurora.org/external/imx/imx-manifest -b imx-linux-thud -m imx-4.19.35-1.0.0.xml
MACHINE=imx8mmevk DISTRO=fscl-wayland source setup-environment build
I really don't want any graphics so it looked like fscl-wayland was my best choice.
Sticker on the bottom of my IMX8MM says "REV B" if that matters.
I tried to compare the FAT boot partition of the sdcard image that came with the board with the sdcard image of my new build and the most notable difference is the number and names of the .dtb's.
I don't see any kernel messages so it looks like it hung in u-boot by not being able to train the DDR4 memory. I'm new to NXP processors (but not Yocto) so there is probably a step I missed somewhere but not sure what it is ... thus this message!