********************************************************************************
*** BUILD SCRIPT FOR RASPBERRY PI 64-BIT KERNEL BUILD                        ***
*** Allan's Workshop                                                         ***
*** https://www.drassal.net/wp/raspberry-pi-64-bit-linux-kernel-rebuild      ***
*** Revised 2025-01-12                                                       ***
********************************************************************************


*** THIS SCRIPT IS NOT INTENDED TO BE DIRECTLY EXECUTED
*** COPY/PASTE EACH SET OF COMMANDS IN SEQUENCE


*** create a Raspberry Pi micro sd card
*** replace /dev/sda with the micro sd card device
*** for example change /dev/target to /dev/sda
*** be careful and do not mistake the device
*** for exmaple change /dev/targetpartition to /dev/sda1

*** be sure the device and all partitions are unmounted first
sudo umount /dev/targetpartition

*** copy the image onto the micro sd card
xzcat /var/datadisk/raspberrypi/2024-11-19-raspios-bookworm-arm64-full.img.xz | sudo dd of=/dev/target

*** flush the buffer to ensure all data is written to the micro sd card
sync





*** INSERT THE MICRO SD CARD INTO THE RASPBERRY PI
*** POWER UP THE RASPBERRY PI
*** COMPLETE THE INITIAL RASPBERRY PI SETUP NOW
*** COMPLETE ANY SETUP REQUIRED TO ESTABLISH AN INTERNET CONNECTION
*** ENABLE SSH NOW (if desired)

*** IF INTERNET CONNECTION IS NOT POSSIBLE THEN PRE DOWNLOAD THE RASPBERRY PI KERNEL SOURCES FROM GITHUB
*** git clone --depth=1 https://github.com/raspberrypi/linux





*** ssh into the raspberry pi
*** or open a terminal on the raspberry pi

*** change to super user
sudo su

*** SETUP ENVIORNMENT VARIABLES
NOW_YMDHMS=$(date +"%Y%m%d%H%M%S")
NOW_YMD=$(date +"%Y%m%d")
DATESTAMP=${NOW_YMD}
WORKROOT=/media/pi/e65e2c06-9254-4d71-b75e-3e407c807acf
WORKDIR=${WORKROOT}/kernel_build_${DATESTAMP}
BOOTDIR=/boot/firmware
KERNELMODULESDIR=/lib/modules





*** prepare the raspberry pi directory
rm -rf ${WORKDIR}
mkdir ${WORKDIR}
cd ${WORKDIR}





*** install required tools
apt install git bc bison flex libssl-dev make libc6-dev libncurses5-dev





*** download and prepare the kernel sources on the raspberry pi

*** get the current kernel
rm -rf ${WORKDIR}/linux
git clone --depth=1 https://github.com/raspberrypi/linux

*** set the kernel version

*** parse and display the version
#kernel version found in kernel Makefile, at the top (VERSION, PATCHLEVEL, SUBLEVEL)
filename="${WORKDIR}/linux/Makefile"
KERNEL_VERSION=$(grep -m 1 VERSION $filename | sed 's/^.*= //g')
KERNEL_VERSION=${KERNEL_VERSION}.
KERNEL_VERSION=${KERNEL_VERSION}$(grep -m 1 PATCHLEVEL $filename | sed 's/^.*= //g')
KERNEL_VERSION=${KERNEL_VERSION}.
KERNEL_VERSION=${KERNEL_VERSION}$(grep -m 1 SUBLEVEL $filename | sed 's/^.*= //g')
echo "KERNEL_VERSION="${KERNEL_VERSION}

*** archive downloaded files for possible use later
tar -jcvpf ${WORKDIR}/linux_${KERNEL_VERSION}_${DATESTAMP}.tar.bz2 --directory=${WORKDIR}/linux .





*** ON THE RASPBERRY PI (or in the SSH session)
*** configure and build kernel (kernel8)
*** for the following models
#Architecture 64-bit
#Models
# Raspberry Pi 3
# Raspberry Pi Compute Module 3
# Raspberry Pi 3+
# Raspberry Pi Compute Module 3+
# Raspberry Pi Zero 2 W
# Raspberry Pi 4
# Raspberry Pi 400
# Raspberry Pi Compute Module 4
# Raspberry Pi Compute Module 4S
*** configure the build
cd ${WORKDIR}/linux
KERNEL=kernel8
make bcm2711_defconfig

*** must add btrfs filesystem support to as built-in, not module
make menuconfig
*** File systems -> Btrfs filesystem support
*** change M to y

*** Customize the kernel version using LOCALVERSION
#To prevent the kernel from overwriting existing modules in /lib/modules and to clarify that you run your own kernel in uname output, adjust LOCALVERSION.
#To adjust LOCALVERSION, change the following line in .config:
#CONFIG_LOCALVERSION="-v7l-MY_CUSTOM_KERNEL"

*** Run the following commands to build a 64-bit kernel:
make -j6 Image.gz modules dtbs

*** prepare the kernel modules
rm -rf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules
make -j6 INSTALL_MOD_PATH=${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules modules_install

*** archive the modules for later use
tar -jcvpf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules_${DATESTAMP}.tar.bz2 --directory=${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules/lib/modules/ .

*** archive the 64-bit kernel:
*** archive the kernel and kernel config
rm -rf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}
mkdir -p ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}
cp arch/arm64/boot/Image.gz ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}/${KERNEL}.img
cp .config ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}/${KERNEL}.config
tar -jcvpf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_${DATESTAMP}.tar.bz2 --directory=${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}/ .

*** archive backup the overlays:
*** archive the overlays
rm -rf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb
mkdir -p ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb
cp arch/arm64/boot/dts/broadcom/*.dtb ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/
mkdir -p ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/overlays
cp arch/arm64/boot/dts/overlays/*.dtb* ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/overlays/
cp arch/arm64/boot/dts/overlays/README ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/overlays/
tar -jcvpf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb_${DATESTAMP}.tar.bz2 --directory=${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/ .










*** ON THE RASPBERRY PI (or in the SSH session)
*** configure and build kernel (kernel_2712)
*** for the following models
#Architecture 64-bit
#Models
# Raspberry Pi 5
*** configure the build
cd ${WORKDIR}/linux
KERNEL=kernel_2712
make bcm2712_defconfig

*** must add btrfs filesystem support to as built-in, not module
make menuconfig
*** File systems -> Btrfs filesystem support
*** change M to y

*** Customize the kernel version using LOCALVERSION
#To prevent the kernel from overwriting existing modules in /lib/modules and to clarify that you run your own kernel in uname output, adjust LOCALVERSION.
#To adjust LOCALVERSION, change the following line in .config:
#CONFIG_LOCALVERSION="-v7l-MY_CUSTOM_KERNEL"

*** Run the following commands to build a 64-bit kernel:
make -j6 Image.gz modules dtbs

*** prepare the kernel modules
rm -rf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules
make -j6 INSTALL_MOD_PATH=${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules modules_install

*** archive the modules for later use
tar -jcvpf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules_${DATESTAMP}.tar.bz2 --directory=${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules/lib/modules/ .

*** archive the 64-bit kernel:
*** archive the kernel and kernel config
rm -rf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}
mkdir -p ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}
cp arch/arm64/boot/Image.gz ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}/${KERNEL}.img
cp .config ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}/${KERNEL}.config
tar -jcvpf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_${DATESTAMP}.tar.bz2 --directory=${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}/ .

*** archive backup the overlays:
*** archive the overlays
rm -rf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb
mkdir -p ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb
cp arch/arm64/boot/dts/broadcom/*.dtb ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/
mkdir -p ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/overlays
cp arch/arm64/boot/dts/overlays/*.dtb* ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/overlays/
cp arch/arm64/boot/dts/overlays/README ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/overlays/
tar -jcvpf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb_${DATESTAMP}.tar.bz2 --directory=${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb/ .









*** at this point new kernel and kernel modules have been created
*** next step is to update the sd card with the new kernel










*** backup the current bootfs if needed
tar -jcvpf ${WORKDIR}/bootfs_${DATESTAMP}.tar.bz2 --directory=${BOOTDIR} .





*** restore the bootfs from backup if needed
*** first blow away the bootfs
rm -rf ${BOOTDIR}/*
*** verify the current bootfs is empty
ls -la ${BOOTDIR}
*** next, restore the bootfs from backup
tar xjf ${WORKDIR}/bootfs_${DATESTAMP}.tar.bz2 -C ${BOOTDIR}
*** verify the current bootfs is now populated
ls -la ${BOOTDIR}










*** copy the new kernel to the bootfs
*** for kernel8 (raspberry pi 3, 3a, 3a+, 3b, 3b+, 4, cm4, 400, zero, 2w
KERNEL=kernel8
tar xjf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_${DATESTAMP}.tar.bz2 -C ${BOOTDIR} ./${KERNEL}.img
*** dtb files should be same for all kernels
tar xjf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb_${DATESTAMP}.tar.bz2 -C ${BOOTDIR}

*** optional but recommended to retain a copy of the kernel configuration
tar xjf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_${DATESTAMP}.tar.bz2 -C ${BOOTDIR} ./${KERNEL}.config





*** copy the new kernel to the bootfs
*** for kernel_2712 (raspberry pi 5)
KERNEL=kernel_2712
tar xjf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_${DATESTAMP}.tar.bz2 -C ${BOOTDIR} ./${KERNEL}.img
*** dtb files should be same for all kernels
#tar xjf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_dtb_${DATESTAMP}.tar.bz2 -C ${BOOTDIR}

*** optional but recommended to retain a copy of the kernel configuration
tar xjf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_${DATESTAMP}.tar.bz2 -C ${BOOTDIR} ./${KERNEL}.config





*** copy the kernel modules to the rootfs
*** blow away the current modules if desired
rm -rf ${KERNELMODULESDIR}/*





*** copy kernel modules to the rootfs
*** for kernel8 (raspberry pi 3, 3a, 3a+, 3b, 3b+, 4, cm4, 400, zero, 2w
KERNEL=kernel8
tar xpjf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules_${DATESTAMP}.tar.bz2 -C ${KERNELMODULESDIR}





*** copy kernel modules to the rootfs
*** for kernel_2712 (raspberry pi 5)
KERNEL=kernel_2712
tar xpjf ${WORKDIR}/linux_${KERNEL_VERSION}_${KERNEL}_modules_${DATESTAMP}.tar.bz2 -C ${KERNELMODULESDIR}










*** run the below command after restart to verify the new kernel is running
cat /proc/version
*** sample output below
pi@raspberrypi:~ $ cat /proc/version
Linux version 6.6.70-v8-16k+ (root@raspberrypi) (gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #2 SMP PREEMPT Sun Jan 12 03:38:56 JST 2025