How do I access .img files with yaffs2? I've tried mounting them in Ubuntu, no luck, mount does not recognize the yaffs2 file system. I've tried yaffs2utils and ./unyaffs2 but it doesn't actually unpack the img files, I've posted an issue about this on the Google Code page here.

The img files were created by CWM Recovery as a backup, and I'm trying to dig into the file system to find old contacts, and if I could just get the .db files I think I got it from there (I'll just run sqlite3 and peek into the db and print the contacts on paper or something).

Any help appreciated!
To unpack a YAFFS2 image, you can use the free unyaffs tool, which is available as pre-build ELF-binary (for Linux) from this page at code.google.com. This page also contains hints on how to obtain the source code, so you could build the binary yourself e.g. with gcc (gcc -o unyaffs unyaffs.c).

I use this tool myself, it works fine on Ubuntu 8.04 32bit as well as Ubuntu 12.04 64bit (with the ia32-libs package installed).

Place the binary e.g. in /usr/local/bin (which is in your $PATH), so you can access it from everywhere. Put the image file you want to extract in an empty directory (unyaffs always seems to extract files directly into the folder the image file is in), and then call unyaffs with the image file name as only parameter, e.g. unyaffs data.img. After that, you will find the contents of that file system/image unpacked, and can investigate them -- e.g.


SMS/MMS in data/com.android.providers.telephony/databases/mmssms.db
Multimedia Metadata in data/com.android.providers.media/databases/*.db
Calendar data in data/com.android.providers.calendar/databases/calendar.db


As I just investigated a MotoBlur image, contacts in my case have been stored to data/com.motorola.blur.providers.contacts/databases/contacts2.db -- they are probably in a different location in your case (a guess: data/com.android.providers.contacts/databases/*.db).

The sqlite3 command works on them, naturally. If you prefer a graphical frontend, I can recommend you the sqliteman package (comes with a binary of the same name, which accepts the database file as parameter).