Compiling simg2img and make_ext4fs from Android v4.2.1 sources

http://muzso.hu/2012/08/10/how-to-pack-and-unpack-system.img-and-userdata.img-from-an-android-factory-image#comment-1678

gcc compiling option should be re-located, which is supposed to depends on the computer environment.

Compiling simg2img and make_ext4fs from Android v4.2.1 sources

The process is a bit different now.
Let's assume that the $AOSP_ROOT variable points to our AOSP root (eg. export AOSP_ROOT="$HOME/Android/AOSP").

1. Download the https://android.googlesource.com/platform/system/core repository:
   
   cd "$AOSP_ROOT"
[ ! -d "platform/system" ] && mkdir -p platform/system
cd platform/system
git clone https://android.googlesource.com/platform/system/core
2. Check out a revision of your choice:
   
   cd core
git checkout android-4.2.1_r1
3. Compile simg2img:
   
   cd libsparse
gcc -o simg2img -Iinclude -lz simg2img.c sparse_crc32.c backed_block.c output_file.c sparse.c sparse_err.c sparse_read.c
gcc -o simg2img -Iinclude simg2img.c sparse_crc32.c backed_block.c output_file.c sparse.c sparse_err.c sparse_read.c -lz
   (When compiling, the link option should come at last on my computer. If not "undefined reference to xxxx" errors happened.)
   

The unpacking is quite the same:

• Unpack your Android image files (of course you should adjust the commands for the correct path to the IMG files):
  
  cd ../../
./core/libsparse/simg2img system.img system.raw.img
./core/libsparse/simg2img userdata.img userdata.raw.img
• Do whatever you want with the images (eg. you can use Paragon's ExtFS on a Mac or just simply mount the images in linux via the loop device). Eg.
  
  mkdir /mnt/my_system /mnt/my_userdata
mount -t ext4 -o loop system.raw.img /mnt/my_system
mount -t ext4 -o loop userdata.raw.img /mnt/my_userdata

And the compilation of make_ext4fs did get more complicated too:

1. Download the https://android.googlesource.com/platform/system/extras repository:
   
   cd "$AOSP_ROOT/platform"
[ ! -d "system" ] && mkdir system
cd system
git clone https://android.googlesource.com/platform/system/extras
2. Check out a revision of your choice:
   
   cd extras
git checkout android-4.2.1_r1
3. Compile make_ext4fs:
   
   cd ..
gcc -o make_ext4fs -Icore/libsparse/include -lz extras/ext4_utils/make_ext4fs_main.c extras/ext4_utils/make_ext4fs.c extras/ext4_utils/ext4fixup.c extras/ext4_utils/ext4_utils.c extras/ext4_utils/allocate.c extras/ext4_utils/contents.c extras/ext4_utils/extent.c extras/ext4_utils/indirect.c extras/ext4_utils/uuid.c extras/ext4_utils/sha1.c extras/ext4_utils/wipe.c core/libsparse/backed_block.c core/libsparse/output_file.c core/libsparse/sparse.c core/libsparse/sparse_crc32.c core/libsparse/sparse_err.c core/libsparse/sparse_read.c

And the repacking is all the same too:

PATH="$PATH:$(pwd)" ./extras/ext4_utils/mkuserimg.sh -s /mnt/my_system_dir my_system.img ext4 /tmp 512M