Stuck in uboot because of serial data input

I’m experiencing a problem
it looks that data coming from external device on serial0 is causing uboot to exit standard autoboot and interrupting the wall boot
as u boot for converted mender images looks modded for mender can you please help me to set up silent boot with no boot delay in order to avoid waiting for for data on console for exiting boot sequence as explain here https://raspberrypi.stackexchange.com/a/117951
at least just say me where I can find the mender modded Uboot repo in order to add my config inside and recompile it
thanks a lot for you help

Hi @profff our u-boot fork is here.

Drew

On a RPI2, I solved the uboot issue when an external device is connected on serial0 with :

fw_setenv stdin nulldev
fw_setenv stderr vidconsole
fw_setenv stdout vidconsole