Is it possible to modify the kernel and shell of an android device? Devices like Samsung Galaxy S6 or Xiaomi Mi4i? If yes, how is it possible? Does the Manufacturer need to provide the Kernel before development? Can we use any kernel in any Android device
Kernel yes, shell don't know of there is any way. By the way shell is the command line interface of android that you can access by rooting, and using busy box or adb. You can't change that as it is architecture based. Just like you can't change cmd on windows to use Mac commands. But if you are taking about firmware, then yes, ROM yes, recovery yes, boot loader no. If it answers your question.