I have successfully signed and authenticated u-boot, the kernel image, the device tree blob, the entire root file system and a select portion of the root file system (used for faster boot up) on both the imx8mq-evk and the imx8mm-evk.
Unfortunately, I haven't had the same level of success with encryption. I believe one of the issues is that the RNG is not active on the EVK so I could not create the DEK blob. I could use help with the following item.
There are guides for HAB4 that can be found in the Yocto build. The following three guides can be found in my build at: