How can i completely disable the debug UART console?

Unfortunately, it is.
the project was built around the Colibri iMX8X module, and the debug UART thing was unbeknown to us at the time.
We manage to make a few patches to correct that using TorizonOS, but now we’re on the path to build a customized Linux with Yocto.
Besides compiling the image with no problem, I couldn’t apply the patches successfully.
At first, I’ve tried many things, but let’s start with this/this.
But then I received this error msg,
error-bitbake (4.8 KB)
Can you see where i’m wrong?

Thanks in advance.
Caio Mendes.

Update#1:
I’ve applied successfully the patches in the U-boot, as described by the link above.
However, the msgs I am seeing are from the kernel console. I can diminish, but not eradicate.