I work with thw Viola Board V1.2B and use an i.MX6ULL with the Image:Colibri iMX6ULL (2.8b4 | 2018-10-05)
The UART connection the the terminal on the Linux Host works fine.
I cannot stop the U-Boot with any key on boot phase ?
What can be the reason ? (Ii seems do be no hardware problem, because Terminal works fine with UART)