Select U-Boot version in DEY 4.0 for ccimx6ul

DEY Yocto 4.0 defines U-Boot 2020.04 as the default boot loader for ccimx6ul.
For some reasons I would like to use U-Boot 2017.03 instead, which is also bundled in DEY 4.0 and usable for ccimx6ul according to its “COMPATIBLE_MACHINE” tag.

Where is the correct location in the Yocto layers to set this U-Boot version?

The U-boot version is tied with the Yocto version of the release. By rolling back a U-boot version, you might be losing new features advertised in DEY 4.0 as they might be part of the U-boot. If you insist on using a separate version of U-boot, I’d suggest building it separately from sources in GitHub. For U-Boot 2017.03 please use

I can provide more specific instructions on doing so if neccesary

I understand.
The reason why I want to use v2017.03: In our project we use a customised version of DEY U-Boot 2015 on a ConnectCore 6UL based device. This old U-Boot is perfectly sufficient for our requirements. Only for the rest of the software we are on DEY 4.0.

Now I have to extend this U-Boot for the possibly used new type of NAND flash in the cc6ul modules. To my knowledge, the required patches made by Digi are only available for v2017.03 and v2020.04, but not for v2015.
So - as our device is in the “autumn” of its life but is still produced - I want to use v2017.03 which works with the new NAND flash and is still quite similar for our own board adaptions (which I have to port from v2015 to v2017).

Yes, I will use the U-Boot v2017.03 project of Digi to create the customised U-Boot outside of DEY.
I may follow up with questions after having set up a build environment.