README-REF

# Update upstream to most recent LTS version
```sh
git switch linux-6.6.y-ref
git remote add kernel.org https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
git fetch kernel.org
git rebase kernel.org/linux-6.6.y
```

# Build the kernel
```sh
# Switch into the custom kernel source tree
cd ref-linux

# Install the dependencies needed for building the Linux kernel
sudo apt install build-essential bison flex bc lz4 libssl-dev debhelper libelf-dev pahole

# Copy the current kernel config and use it as a starting point for the new kernel.
cp /boot/config-<...> .config

# Disable kernel signing
scripts/config --disable CONFIG_SYSTEM_TRUSTED_KEYS
scripts/config --disable CONFIG_SYSTEM_REVOCATION_LIST
scripts/config --disable MODULE_SIG_KEY

# Set default values for config attributes not found in the copied config.
make olddefconfig

# Add custom suffix to the kernel's name
scripts/config --set-str CONFIG_LOCALVERSION 'ref'

# Build the kernel as .deb package. The files will be located in the parent directory.
make -j$(nproc) bindeb-pkg

# Install the packages
dpkg -i linux-*.deb
```