Thanks for your answer, from my understanding the solution based on torizonCore Builder is only in a “custom” kernel building, am I wrong ?
TorizonCore Builder does not in any case re-build the linux kernel itself. It only makes small modifications. In this case all it would be doing is appending kernel arguments to the existing kernel command line. This does not require building a custom kernel.
Regarding the U-Boot solution, which seems to answer my request of updating the kernel cmdline without the need of building a custom kernel, do you have any guide to ease the implementation of this solution ?
It’s fairly self explanatory, you just need to set a value of tdxargs in U-Boot. Whatever is in tdxargs gets appended to the kernel command line. If tdxargs is equal to foo then foo will be appended onto the kernel command line. If you don’t know how to modify environment variables in U-Boot then look here: U-Boot | Toradex Developer Center
Best Regards,
Jeremias