Part 1 - How to unpack (unyaffs) system.img and cache.img files directly on the WPDN
This can obviously be done from a pc/mac, but here is another option to accomplish this directly on the WPDN itself.
This app isn't necessarily exclusive to the WPDN, I've used it on my phone also to extract system.img & cache.img files, so it should work on most rooted devices.
There is more functionality to the app, but that is not the focus of this tutorial (see note #2 below).
IF you read and follow the directions here, there is no risk to your device as you are simply unpacking an .img file onto our
SDCard. With the unpacked .img file, you can access all of the system files/apps and user apps from the STOCK system and cache.img files that come with the STOCK FW packages.
Rooted Device. How do you know if you're rooted? You likely already are (especially if you're running one of the custom FW's from
around here). If not, check out KG's combos/patches or full FW replacements.
Anyone will do, you'll use it to pull files from a stock FW package.
From the WPDN 2011 FW's, you can use the system.img and the recovery.img
I've always used 7zip for FW flashing related items, and winrar for everything else.
Yes, it is free (https://market.andro...y.android.yaffs) but has ads. Still works just fine, though. If you so wish,you can donate to the app developer if you find it useful- I don't receive anything from it at all, however just wanted to give an
opportunity for him since he put some serious work into it. You could also purchase the "pro" version which is ad
free (https://market.andro...ndroid.yaffspro). So a special thanks to Joey Jiao for
all of his work on this to add some support for the WPDN. But may no longer be available in the Play store. Anyhow- as before:
By permission of the dev- here's the direct link to the apk http://www.mediafire.com/?6ah7uy0w5bvzi13
This app has been tested and revised over and over and now works quite well (especially with the WPDN). I
worked with the developer of the app for several months to help get the WPDN with some support in it. If you want
more details, I'll be more than happy to share any and everything I've got- let me know, but for now let's keep
focus on this tutorial.
This app has more functionality to it that will be focused on in the next tutorial (i.e. like creating
backup files that can be replaced in the FW to create a flashable system backup/restore) -- AGAIN-- THIS EXTRA
FUNCTIONALITY WILL BE HIGHLIGHTED IN THE NEXT TUTORIAL "CREATING FLASHABLE BACKUPS USING YOUR WPDN". YOU CAN BRICK
YOUR DEVICE AND RENDER IT RECOVERABLE IF YOU ARE NOT CAREFUL. The reason is that the extra functionality is shared
with other devices that can make full use of it. And the functionality itself does not yet write the /data/apps to its respective location- it is my hopes by sharing what this DOES do, we'll get some folks on board to get the last piece of this going and possibly see full flashable backups on the WPDN.
Yes, the screenshots (added below) were taken on a different device, but the operations and processes work the same on the
WPDN. The only reason I chose share screenshots off of another device is entirely because the WPDN does not allow
for screenshots from itself. (The other option would have been to take pictures with a still camera of the WPDN,
which would have been hit or miss because of the lighting,screen protector- etc.)
At any rate- there's screenshots for a visual -- the only "extras" are the icons in the left corner and I don't see
the need to photoshop them out- the point is to illustrate step-by-step on how to use the apk to get to an unyaffed
system and userdata .img file and that's all that matters.
Since these screenshots had to be taken on another device and I use "Astro Filemanager" on that device, it the output folder view will vary slightly. But Astro isn't required on the WPDN. You can achieve the same thing using the Estrong's File Explorer that comes stock with the WPDN- the screens may vary slightly, but the principle is the same- you use it to look at your directory and unzip a file on your device (if you choose). AND that doesn't take away from the fact that this was tested many times over and works on the WPDN.
1) Install YaffsExpert from the market. Once installed, make a directory called "yaffsexpert" on your
SDCard. If not, then create new directory on your sdcard named "yaffsexpert" or something easy like that.
2) Connect your device via USB and copy over the system.img or cache.img from your WPDN firmware package. You could
also unpack the package directly on the device and copy over the appropriate files to another directory within the
device. Either way, put these somewhere on the card you can get to them easily. I recommend the same folder that was
created above. You can create a seperate folder for them also, doesn't matter- just know what and where you placed
them and how to get to them.
3) You MUST have these options selected for this to work, anything else (as far as this tutorial is concerned) is your own doing- stick to the plan.
Main Action Type:
Unpack Img File
Sub Action Type:
(this is where you want your files to be unpacked to- the directory you created):
Enter path the path, i.e. "/sdcard/yaffsexpert"
or press "Browser" long press the folder > select and then press the back arrow.
You can also make a directory by selecting "..." , long press "SDcard" then "MKDIR" and name it.
(this is the location of the .img file to unpack - in the example, it is placed at the root of the sdcard):
Target Device Model:
Pandigital WPDN 7
Before selection "Operation" be sure all your settings are correct.
If you chose the system.img file, you can navigate to the /sdcard/yaffsexpert folder and you will see all the files that normally get packed up in the /system directory on the WPDN. This includes the build.prop file & the /system/app folder that includes all of the sytem apps.
If you chose the cache.img file, you can navigate to where you unpacked it and you will see a "recovery" folder. Within that is a zip file named "user_default_data.zip". If you uncompress that file, you will get to 2 folders - user & apps.
The user folder contains all the goodies that wind up on the internal sdcard (like the usermanual, sample epub stuff, folders, sample pictures, etc.).
The apps folder contains the /data/apps that come rolled in the stock FW (i.e. B&N reader,Office suite,etc.)
Edited by sainthooligan, 28 December 2012 - 09:23 AM.