Shutdown Image Hack

WARNING: this is an outdated version of the hack. Please go to this page of the blog for the current version.
 
Warnings:

• this procedure could only be used when your Nook firmware version is the original 1.5.0 by B&N or any derived firmware (like softroot firmware 2.5.1); applying this procedure when your firmware (you can check your firmware version on Settings page of your Nook) is a different one, will probably lead to your reader not working anymore; 
• applying this procedure you will void your warranty and you may even brick your Nook; i don't take any responsibility in the (unlikely) event something goes wrong while executing the below mentioned procedure.

By default, when you power off the Nook reader (long-clicking the power button) the eInk display will be set with an all-white image (i.e. no image at all).
As you probably already know, a nice eInk display feature is that they don't need any power to display any kind of image: the power is only needed during page transitions. Therefore it is possible to let the Nook display any given image when it is powered off without any effect on battery life.
Unfortunately, this (pretty useless, i admit; it is just "for fun") feature is not present on original Nook firmware, so i decided to implement it with a small modification of firmware (actually, of an android system library).
The modification is pretty harmless (even after installation, it will preserve the original behaviour by default), but as usual in these cases, you must be aware that there is a (remote) chance your Nook will not work correctly after applying the hack (but, this unlikely event should happen, you could normally be able to reflesh latest original firmware).
And, of course, the modification could only be done on rooted Nook.


Installation:

1. verify you have root access to your Nook; a short tutorial on how to get it here; 
2. download the shutdown image hack files:
   • current version:
     shutdown_image_hack.7z (31/12/2010, sha1: 0382be0786184d7b5cd738aa08ae4e9c538e6fb7)
3. create a folder on you PC (let's call it C:\shutdownHackFolder), and then unpack the downloaded file on that folder;
4. connect to your Nook through ADB (either over USB or Wi-Fi); if you don't know what this means, you can find more details here;
5. make a backup of files on Nook we are going to modify (in case you want to rollback this modification):

   adb pull /system/framework/android.policy.jar C:\shutdownHackFolder\original\
   

6. copy files downloaded in step 1. on Nook:
   

   adb push C:\shutdownHackFolder\android.policy.jar /system/framework
   

7. reboot your Nook.

Usage:

• If you want to use a shutdown image:
  1. On internal Nook sd-card (i.e. the one that by default is called "Nook" in Windows explorer, and that contains folders "my documents", "my screensavers", "my wallpapers"), create folder "settings" (lowercase);
  2. put the image you want to use into this folder; png, gif, jpg format are supported; rename this image as "shutdown.<extension>";
     ny image size could be used (a resize mechanism is used); but to get best result, it is better to use image whose size is 600 x 800 pixel;
  3. during shutdown procedure, the Nook will check if into folder "settings" there is a file called shutdown.raw (i.e. the shutdown image in Nook native format); if it's present (and is suitable), that file will be used as shutdown image.
     Otherwise, if an image called "shutdown.<jpg|gif|png>" exists, it will be converted into Nook native format (therefore shutdown.raw will be created) and it will be used as shutdown image.
     If no image is found, the default behaviour would be applied (i.e. white screen would be displayed).
• If you don't want to use a shutdown image (i.e. you want to revert to default behaviour):
  1. simply remove any file called shutdown.* into folder "settings", or the folder itself.