Yocto add U-Boot variables

so I still have the auto-boot for it? On bootcmd_run itself maybe?

I mean yes. If you look at the actual boot script here: meta-toradex-torizon/recipes-bsp/u-boot/u-boot-distro-boot/boot.cmd.in at scarthgap-7.x.y · torizon/meta-toradex-torizon · GitHub

You can see it loads the environment variables from uEnv.txt then it executes bootcmd_run as the final command. Therefore whatever is defined in bootcmd_run is what will get executed.

Best Regards,
Jeremias