Assume you are familiar with TI Jacinto SDK build setting up. Make sure your NB is connecting to the network while building. Because the uboot might referencing the ti github. The working copy cmd is as this, you need to change according the red parameters (root).

Boot Switch setting:

This step is no needing to touch the boot switch on the EVM.

Patches:

• 01 - Remove-prints-to-optimize-U-Boot-time.patch (this patch is here: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1105700/dra821u-application-note-how-to-linux-fast-boot-on-dra821u-putting-the-required-2-patches-here)

Cmds: (Do this on ubuntu, not the EVM)

cd $PSDKLA/board-support/u-boot-2021.01+gitAUTOINC+53e79d0e89-g53e79d0e89/
git am 0001-Remove-prints-to-optimize-U-Boot-time.patch
cd ../..
make u-boot

cp board-support/k3-image-gen-2021.05/tiboot3.bin board-support/u-boot_build/a72/tispl.bin board-support/u-boot_build/a72/u-boot.img /media/root/boot/