latest stable kernel rpi4 code example
Example: raspberry install last kernel
$ sudo apt-get update
$ sudo apt install --reinstall libraspberrypi0 libraspberrypi-{bin,dev,doc} raspberrypi-bootloader raspberrypi-kernel
$ sudo apt-get update
$ sudo apt install --reinstall libraspberrypi0 libraspberrypi-{bin,dev,doc} raspberrypi-bootloader raspberrypi-kernel