Linux

apt install build-essential libncurses-dev bison flex libssl-dev libelf-dev
mkdir /RaspKernel_6_1_y && cd /RaspKernel_6_1_y
git clone --depth=1 --branch rpi-6.1.y https://github.com/raspberrypi/linux
cd linux
cp /boot/config-6.1.93 /RaspKernel_6_1_y/linux/.config
KERNEL=kernel8
make menuconfig
time make -j$((`nproc` - 2)) Image.gz modules dtbs
make -j$((`nproc` - 2)) modules_install
cp arch/arm64/boot/Image.gz /boot/broadcom/$KERNEL.img
cp arch/arm64/boot/dts/broadcom/*.dtb /boot/broadcom/
cp arch/arm64/boot/dts/overlays/*.dtb* /boot/firmware/overlays/
cp arch/arm64/boot/dts/overlays/README /boot/firmware/overlays/
reboot
apt install cryptsetup

#!/bin/sh -e

# Rebuild initrd.gz after kernel upgrade to include new kernel's modules.
# https://github.com/Robpol86/robpol86.com/blob/master/docs/_static/initramfs-rebuild.sh
# Save as (chmod +x): /etc/kernel/postinst.d/initramfs-rebuild

# Remove splash from cmdline.
if grep -q '\bsplash\b' /boot/cmdline.txt; then
  sed -i 's/ \?splash \?/ /' /boot/cmdline.txt
fi

# Exit if not building kernel for this Raspberry Pi's hardware version.
version="$1"
current_version="$(uname -r)"
case "${current_version}" in
  *-v7+)
    case "${version}" in
      *-v7+) ;;
      *) exit 0
    esac
  ;;
  *+)
    case "${version}" in
      *-v7+) exit 0 ;;
    esac
  ;;
esac

# Exit if rebuild cannot be performed or not needed.
[ -x /usr/sbin/mkinitramfs ] || exit 0
[ -f /boot/broadcom/initrd.gz ] || exit 0
lsinitramfs /boot/broadcom/initrd.gz |grep -q "/$version$" && exit 0  # Already in initramfs.

# Rebuild.
mkinitramfs -o /boot/broadcom/initrd.gz "$version"