Hello, thank you for your answers.
I have not tried modifying p3448-0000.conf.common yet, but I think this will only allow to add arguments to command line as those transferred from earlier boot stages (also this may allow for some clean-up of the redundant args). I’ll try this and let you know.
As for the device tree way, the bootargs given in platform/t210/porg/tegra210-porg-p3448-common.dtsi are not found in the final cmdline, although the file is actually used (I’m sure it is because I’m adding a /dev/pps0 entry and this works)
Could it be a typo bootargs vs. cbootargs that prevents this art from actually being used ?