I have seen this asked a few times recently so I figured I would try to put together a quick and easy guide to extracting files from Nandroid backups. This guide only covers Windows, I assume if you are running Linux you can download unyaffs and compile/run it without my assistance. If you are adventurous you can install cygwin and compile unyaffs on your own (or download it at any number of sites across the internet), however I have included all the files needed to extract the files from the img files.
1. Download unyaffs along with the cygwin1.dll
2. Extract the files to a new folder.
3. Copy the system.img file from the ROM or your Nandroid backup to the folder you extracted unyaffs.exe and cygwin1.dll to.
4. Open a command prompt and cd to the folder containing the three files. If you are on Windows 7 you can just navigate there with Windows Explorer and in the URL bar type cmd to open a comman prompt in that location.
5. Type unyaffs system.img
You have now extracted all the files from the system partition of your Nandroid backup. The APKs are in the /app folder and some apps require library files that can be found in the /lib folder. For example: Swype.apk requires that libSwypeCore.so be in the lib folder for it to work properly.
1. Download unyaffs along with the cygwin1.dll
2. Extract the files to a new folder.
3. Copy the system.img file from the ROM or your Nandroid backup to the folder you extracted unyaffs.exe and cygwin1.dll to.
4. Open a command prompt and cd to the folder containing the three files. If you are on Windows 7 you can just navigate there with Windows Explorer and in the URL bar type cmd to open a comman prompt in that location.
5. Type unyaffs system.img
You have now extracted all the files from the system partition of your Nandroid backup. The APKs are in the /app folder and some apps require library files that can be found in the /lib folder. For example: Swype.apk requires that libSwypeCore.so be in the lib folder for it to work properly.