Now, this is going to walk you through doing a few things:
A) Setting up a progam called ADB on your computer so that it can talk to your NG3
B) Adding a "Launcher" app to your nook so that you can access other apps you sideload later
C) Root theNook so that you can do more stuff with the settings, including the ability to...
D) Fix a bug that, after installing a launcher, causes the NG3 to get stuck on the loading screen after rebooting
Before you start, you need to set up ADB on your computer. Follow the instructions linked here. The rest of this post will assume you're using Windows, but won't be hugely different from other OSs.
Here we go:
To set up ADB on your nook:
1. On your Nook, go to Settings>About. You should see the serial number, app version, etc. At the top of that page, there is a nook icon. Tap that icon rapidly until the developer menu opens.
2. Tap "Android Development Settings" and check the box for "USB debugging".
3. At the Developer options screen you are on (where you checked the box), hit the back arrow at the top-left of the screen to go back. But do not exit the developer menu.
4. On your computer, open a command prompt and navigate to the folder where you put adb (in my case I typed in "cd adb/platform-tools")
5. Plug the USB in to the nook. When the nook prompts you to turn on USB mode, do so. At the adb command prompt, type adb devices. ADB should recognize the nook, but say that it is unauthorized.
6. From windows, eject the nook to disconnect nook's file sharing. Once the nook's USB file sharing screen goes away, you should be able to see the developer menu again. Tap "Allow Debugging" one time! There will be no confirmation, just do it one time.
6. Unplug the USB, plug it back in, turn on USB mode when prompted. Back in the command prompt, type adb devices again. This time it should see the device and simply say "device" where it used to say "unauthorized". Congratulations! You can now install a launcher.
To install a launcher, like RelaunchX
1. Download your launcher apk of choice. If you don't know what to pick, try RelaunchX, and download the latest version from plusz's thread here: https://www.mobileread.com/forums/sh...d.php?t=284418 (n.b. To make things easy, ignore his suggestion to get it through F-Droid as you'll need a new launcher to use F-Droid in the first place. Just download the apk).
2. In Command prompt, type adb install <filelocation>, where filelocation is the complete address of the apk. If you have file explorer open, you can just type adb install then a space, then drag the file in to the terminal and it will copy the location for you. (Make sure again that there is a space between "install" and the path or it won't work).
3. ADB should do it's thing and you will get a "success" message in Terminal.
4. Eject the nook from the PC. Shortly after the connection is cut, a window should open on the nook allowing you to select either the nook launcher or your new launcher. If you use RelaunchX, you may get a warning that it wasn't built with this device in mind. You can ignore it, it works great on this device.
This is all great, except there's a bug in how B&N set up the device that only shows up if you install a new launcher. If you reboot the device, you'll be stuck on the boot animation until you do weird things like hold down the power button for a long time to pull up the reboot/power off options (only seems to sometimes work). To fix that, we actually have to disable, remove, or replace the boot animation file itself.
1. Download the modified Glowlight Plus script attached here ("rootGL3.zip" - almost identical to cazar's rooGLP-3 script package, but with one line changing the model number from 510 to 520)
1. Enable USB debugging in Developer options
2. Connect USB cable and make sure your nook is showing up in 'adb devices'
3. Extract rootGLP.zip and run rootnook.cmd (or rootnook.sh on linux)
To fix (read: disable) the buggy boot animation:
1. Connect your nook to the computer again
2. (windows) open a command prompt and and navigate to the folder that adb is in.
3. Enter the following commands, in order:
adb shell su mount -o remount, rw /system mv /system/bin/bootanimation /system/bin/bootanimation.bak reboot
1. Download the attached zip
2. If it's not still connected, connect the Nook to the computer again and tap the button on the nook to turn on USB mode when prompted
3. On your computer, open up the Nook in Explorer(/Finder/your file manager of choice). Open up the NOOK Folder if you see one.
4. Copy the file inside the zip (bootanimation) to that folder on the Nook.
5. (windows) open a command prompt and navigate to the folder that adb is in.
6. Enter the following commands:
adb shell su cp /storage/spsd/NOOK/bootanimation /system/bin/bootanimation mount -o rw,remount -t ext4 /dev/block/mmcblk0p5 /system cd /system/bin chmod 755 bootanimation reboot
Sources for these instructions:
https://www.mobileread.com/forums/sh...&postcount=118 (how to sideload onto nook 3)
https://forum.xda-developers.com/sho...&postcount=113 (same as above, diff user)
https://www.mobileread.com/forums/sh...65#post3632665 (to get RelaunchX)
https://forum.xda-developers.com/sho...php?p=64191791 (for nook GLP rooting script)
https://forum.xda-developers.com/sho...&postcount=127 (to fix boot animation loop)