This is a default configuration for generating a root files system (rootfs) for the Western Digital My Book Live. Now that Debian has declared PowerPC as a end of life architecture, the need for generating and loading a custom Linux OS will be higher to pull in security updates and product patches.
The latest WD My Book Live GPL Source Code can be found at https://support.wdc.com/downloads.aspx?p=132&lang=en
# Install some dependencies to get started (taken from sample vagrant file)
sudo apt update
sudo apt install build-essential libncurses5-dev git libc6:i386 unzip bc libelf-dev
# Clone the master buildroot and MyBookLive-buildroot repos
git clone https://github.com/buildroot/buildroot.git
git clone https://github.com/goldstar611/MyBookLive-buildroot.git
# Copy the MyBookLive defconfig and board package into buildroot directory
cp -R MyBookLive-buildroot/configs/* buildroot/configs
cp -R MyBookLive-buildroot/board/* buildroot/board
# Get additional dependencies for make gconfig
sudo apt install libgtk2.0-dev libglib2.0-dev libglade2-dev
# Load the default configuration for the MyBookLive (A PowerPC 446 architecture)
cd buildroot
make mybooklive_defconfig
make gconfig
# If you chose busybox as init then you can configure some "hidden" options
#make busybox-gconfig
# If you chose uClibc as toolchain then you can configure some "hidden" options
#make uclibc-menuconfig
# If you want to adjust kernel options before compiling
#make linux-gconfig
# After adjusting all build options you should make the top level target
# You should never use make -jN with Buildroot: Instead, configure the BR2_JLEVEL option
make
# If you are building with gcc6 and receive the following error:
# arch/powerpc/kernel/ptrace.c:407:24: warning: index 32 denotes an offset greater than size of 'u64[32][0] {aka long long unsigned int[32][0]}' [-Warray-bounds] offsetof(struct thread_fp_state, fpr[32][0]));
# Then you need to apply patch 35b7ce4f8f290794d3b89db7461e8c568b5defa1
# See https://lists.debian.org/debian-gcc/2016/08/msg00137.html for the patch