I built a u-boot and kernel image using sdbuild. This is for the TUL PYNQ-2 board, so I got the known good SD card image from their website for correct partitioning and replaced the u-boot and kernel images with those that I had built.
The resulting u-boot doesn’t boot the kernel image resident on the 1st partition. The
bootcmd goes through a number of subcommands trying different boot targets, but does not find the petalinux image on mmc partition 1.
As a quick fix, I replaced the u-boot env variable
bootcmd with the following
bootcmd=fatload mmc 0:1 0x2000000 image.ub; bootm 0x2000000
This seems to work fine. I can look for a solution, but did not find a boot script that was similar to the u-boot environment.