Copio de Nook Devs :
http://nookdevs.com/User_talk:NaerymdanIntroduction
This article is for Nooks with:
* Serials # greater than 10031
* Pre-loaded with firmware version 1.4.1, 1.4.2 or 1.4.3
* Currently on any firmware revision (1.4.1, 1.4.2, 1.4.3, 1.5.0)
There is basically 4 steps:
1. Downgrade from 1.5 to stock firmware (the firmware your nook originally came with) At least 1 user's Nook did not actually downgrade to 1.4.X but stayed on 1.5 with this method. Use only to go from official non-rooted 1.5 to rootable 1.4.X, not as a confirmed way of going back and forth between 1.5 and 1.4
2. Root you nook (Means get the ADB daemon inside your nook running)
3. Install means of controlling the ADB daemon (nooklauncher and Nook WiFi Locker)
4. Update to 1.5
[edit] Downgrade from 1.5 to stock firmware
Disregard this step if you are on 1.4.X firmware
This is UNCONFIRMED
1. Remove your account attached to the device.
2. Make sure you have no possible wifi connection
* Unplug wireless router
* Remove password to wifi connections (factory reset is nice for that)
* Run far from public access points (wifi without passwords)
3. Do a Hard Reset
* Hold the power button for 12 seconds, release for 1 second and repeat 6 times
o The screen will flash from white to black
* With a wireless connection, it would just connect to B&N and apply 1.5 again
4. Wait for your Nook to re-install it's own system again
5. Enjoy your 1.4.X nook
[edit] Root you nook
Disregard this step if your 1.4.X Nook is already rooted
Important
Do not completely remove /system/app/FirmwareUpdateService.apk since we need it later on. Renaming it (mv /system/app/FirmwareUpdateService.apk /system/app/FirmwareUpdateService.backup) is a much better idea.
Use one of the following method:
* Applying with Details by Tommy
* Alternative No Router method
Rooting means you have the ADB daemon started on your nook and you can connect to you nook from your computer with the Android SDK's.
You might also be interested to make the ADB daemon start from the rc file:
1. Pull the current rc file from your Nook
adb pull /init.rc init.rc
2. In a text editor, Change the section about adb from "disable" to "enable" in the init.rc file
3. Push the file back into the Nook
adb push init.rc /init.rc
Read more:
http://nookdevs.com/User_talk:Tommy#ixzz16bOpXzqW Under Creative Commons License: Attribution Non-Commercial Share Alike
[edit] Install means of controlling the ADB daemon
Before updating to 1.5, we need to make sure we will still be able to start the ADB daemon inside our nook.
1. Install a new launcher (Nooklauncher
1. Download Nooklauncher from download
2. Put it somewhere you will remember
3. Connect ADB to your nook
adb connect NOOK_IP:5555
4. Install the application
adb install nookLauncher.apk
5. Pull the packages file
adb pull /data/system/packages.xml packages.xml
6. Use a text editor to open the packages.xml file and add the following directly after the <preferred-packages /> tag
<preferred-activities>
<item name="com.nookdevs.launcher/.NookLauncher" match="100000" set="2">
<set name="com.bravo.home/.HomeActivity" />
<set name="com.nookdevs.launcher/.NookLauncher" />
<filter>
<action name="android.intent.action.MAIN" />
<cat name="android.intent.category.HOME" />
<cat name="android.intent.category.DEFAULT" />
</filter>
</item>
</preferred-activities>
1.
1. Push the packages.xml file back into the Nook to make the new launcher default
adb push packages.xml /data/system/packages.xml
2. Install a ADB controller (Nook_WiFi_Locker)
1. Download Nook_WiFi_Locker from download
2. Put it somewhere you will remember
3. Connect ADB to your nook if needed
adb connect NOOK_IP:5555
4. Install the application
adb install nookWifiLocker.apk
3. Restart you Nook
* The lower color screen should now show the new launcher we just installed
4. Add the Nook_WiFi_Locker icon to your launcher
1. Go in LauncherSettings or press and hold an icon
2. Press the + sign
3. Find the Nook_WiFi_Locker in the list and press it's + sign
4. Press the < sign a couple times
5. Try out your newly accessible Nook_WiFi_Locker
[edit] Update to 1.5
1. Re-enable the B&N automatic updating (if you had only renamed it)
mv /system/app/FirmwareUpdateService.backup /system/app/FirmwareUpdateService.apk
2. Update to 1.5
1. Go in the "my library" aplication
2. Press "Check for new B&N content"
3. Wait for the update to download and install, making you Nook restart a couple times
4. Restart your Nook yourself once more
3. Disable the automatic updates again
1. Go in the Nook_WiFi_Locker application
2. Press Start/Stop adb at least once so that it reads "stop adb"
3. Connect from your computer
adb connect NOOK_IP:5555
4. Rename the updating service
mv /system/app/FirmwareUpdateService.apk /system/app/FirmwareUpdateService.backup
5. Restart Nook
4. ???
5. PROFIT!
[edit] Credit
* uberjuice - Downgrading method
* cdump - DNS rooting
* Tommy - Readable tutorial for rooting
* Skwerl23 - Method without router
* naerymdan - Readable 1.5 root tutorial