U-boot build with https://github.com/compulab-yokneam/meta-bsp-imx8mm/blob/iot-gate-imx8-r3.2.1/Documentation/imx_boot_image_build.md

[jyurdal]

I have tried to build bootloader as described in r3.2 referred from compulab wiki page but it failed due to patches incompatibility:

git -C imx-atf am ${LAYER_DIR}/recipes-bsp/imx-atf/compulab/imx8mm/*.patch
}
Applying: imx8mm: Assign RDC_PDAP_UART4 to D0
Applying: iot-gate-imx8: RDC: Remove UART2 D0 restrictions
Applying: imx8mm: Set BL2_BASE to the upper egde of the 1G
Applying: imx8mm: RDC: Remove UART1 D0 restrictions
Applying: imx8mm: Set IMX_BOOT_UART_BASE for CompuLab boards
error: patch failed: plat/imx/imx8m/imx8mm/platform.mk:62
error: plat/imx/imx8m/imx8mm/platform.mk: patch does not apply
Patch failed at 0005 imx8mm: Set IMX_BOOT_UART_BASE for CompuLab boards
hint: Use 'git am --show-current-patch=diff' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

Bootloader update procedure for r3.2 referred from Compulab wiki page misses the boot0 (or simmilar) string in Flashing section

dd if=${RESULTS}/flash.bin of=/dev/ bs=1K seek=33 status=progress

[jyurdal]

I have actually managed to update the bootloader using cl-uboot and found the files in the Yocto build. A small update on https://mediawiki.compulab.com/w/index.php?title=IOT-GATE-iMX8_and_SBC-IOT-iMX8:_Yocto_Linux:_Installation could be helpfull for others.