muffinresearch

git clone https://android.googlesource.com/platform/system/extras
cd extras/ext4_utils
git checkout android-4.1.1_r1
gcc -o simg2img -lz sparse_crc32.c simg2img.c
ln -s ${PWD}/simg2img ~/bin/simg2img

# Last step make sure ~/bin is in your $PATH.