# Notes on how to natively compile (building on the TV box itself) a custom
# kernel and install it with .deb files for amlogic based boxes
# (this may work for other chips (rockchip, allwinner), but I only have
# amlogic boxes to work with)


# This is based on learning how a lot of this works by reading and understanding
# the following thread:
# https://forum.armbian.com/topic/9625-compiling-and-booting-mainline-linux-for-your-s9xxx-tv-box/


# get kernel source
# example: git clone -b linux-5.4.y https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
# get and use an appropriate kernel config file 
# (I use the one from a currently working armbian build)

# Sync git with kernel head if you want or need to get changes
# since you cloned the kernel tree 
git pull

# Apply neccesary patches
# find the appropriate kernel patches from here:
# https://github.com/150balbes/Build-Armbian
# you will need two patches (at a minumum) from the above git repository:
# (depending on what kernel version you will need different versions of
# these patches, generally the 'dev' version will work with latest rc kernels
# and 'current' patches will work with the latest LTS kernel.  To see what
# what kernel version a specific patch was intended to work against, look
# in the corresponding config/sources/families/?????.conf file for the 
# kernel source version for the 'stable', 'current' and 'dev' builds)
#   - patch/kernel/?????/build-????.patch
#   - patch/kernel/?????/text-offset.patch
#
# Depending on your box and desires there are other patches you may or may not
# need.  I am focusing on building stock kernel without extra patches and that
# works for my needs, but your needs may be different.
#

# build the kernel and make the .deb files
# (I use -j4 as I have a 4 core arm cpu, you can adjust as appropriate) 
# (LOCALVERSION=  removes an additional '+' in the name due to patches/changes)
make LOCALVERSION= -j4 bindeb-pkg

# You may need to remove the existing kernel package before installing the 
# new kernel package due to conflicts with the files you are trying to install
# sudo apt remove linux-image-??? 
# By doing this you are breaking your system (by removing the current running
# kernel) and if anything goes wrong you will not be able to reboot.
# You have been warned.  Don't test this on a system you can't afford to lose.

# Install the custom built kernel
sudo apt install /.../linux-image-???.deb


# reboot and if you are lucky the system comes up running your custom kernel
# If you are not lucky there are a thousand reasons why something may not
# be working, you are on your own to figure it out
sudo shutdown -r now