From nookDevs

Part of the NookColor portal

This page contains random tidbits of information that you may find useful for modding your Nook Color.

Please be careful with the commands on this page, as some of them may have harmful effects if used incorrectly.

Contents 1 Android ADB Shell Commands 1.1 Remount /system as rw 1.2 Remount /system as ro 1.3 Recalibrate Your Touchscreen (work in progress!) 2 Re-encode video for NookColor 3 Demo Mode

Android ADB Shell Commands

The commands here are to be issued in an adb shell

Remount /system as rw

This allows you to modify files in /system, and also potentially add su :) Make sure your adb shell prompt is a # and not a $, or else this trick will not work. (ro.secure must be set off)

mount -o rw,remount -t ext2 /dev/block/mmcblk0p5 /system

Remember to remount as ro when you're done!

Remount /system as ro

mount -o ro,remount -t ext2 /dev/block/mmcblk0p5 /system

Recalibrate Your Touchscreen (work in progress!)

If your touchscreen seems to be behaving strangely (phantom taps, etc) you can try the method below:

1. Plug your device in and start adb shell
2. Issue

   echo 2 > /sys/bus/i2c/devices/2-0022/forcecal

3. Wait around 30 seconds - your touchscreen will become unresponsive.
4. Issue

   reboot

   to restart your Nook Color.

This method has worked for me, and is the simplified version of my complete steps. Please report to #nookcolor on IRC if this method doesn't work for you.

Re-encode video for NookColor

According to the hardware specs, the NookColor features a PowerVR SGX530 GPU processor which supports hardware decoding of several video containers and codecs. Of the supported modes, several containers and h.264 encoding options have been tested to see which produce videos that are playable on the NookColor. The following summarizes the results:

Video Containers

Container	Notes
mkv	Not Supported
mp4	Supported

h.264 Encoding Options

Option	Notes
Max Resolution	800x448
Variable Frame Rate	Supported
Variable Bitrate	Supported
8x8 Transform	Not Supported
CABAC	Not Supported
Max B-Frames	0
Max Reference Frames	6
Max Subpixel Motion Estimation Mode	9
Weighted P-Frames	Not Supported
Trellis	Encode only

Audio Codecs

Codec	Notes
AC3	Not Supported
AAC	Supported

Notes:

• Only codecs and containers that have been tested are shown. There are other containers and codecs that will work as well.

• HandBrake was used for encoding. This relies on the x264 library for h.264 encoding and the faac library for AAC encoding.

• mVideoPlayer was used for playback because it apparently relies on the platform's hardware for video playback and does not attempt to do software playback. Other formats and h.264 encoding options may work with other video players but may result in choppy playback and much higher battery drain.

• An exhaustive test on resolutions was not performed. Although the NookColor_Hardware_specs say the device supports hardware scaling of 854x480 video, my sample would not play back at that resolution, even at low bitrates (400 kbps). There were some resolutions higher than 800x448 that would playback but with heavy distortions. At some point they failed to play back at all.

• Videos encoded with more than 6 Reference Frames would play back but with heavy distortions. At some point they failed to play back at all.

• There may be some further dependencies on bitrate, maximum bitrate, or filesize. I had a 10 second sample play back fine but the full-length version fail to play back at all. Lowering the bitrate (from ~2700 kbps, 2.4 GB to ~2100 kbps, 1.7 GB) allowed the full video to play back.

Some people have found information in this thread useful: [1]. It has instructions for Handbrake settings that should work with NookColor for video.

Demo Mode

As of 1.1.0, nook colors in the stores are in "demo mode", which locks down various items in the settings, including (de)registration and the social media aspects of the device, and adds a screensaver loop for when the devices are idle. To access this mode on your nook (rooted or not), go to settings->security, press and hold the volume up button, and tap the speaker icon on the screen that appears. A third menu item, "Demo Mode", will appear, ready to be toggled on or off. Obviously this mode has a serious negative impact on battery life, since the screen no longer sleeps for long periods.

It might be interesting to try and swap out the images that the screensaver displays.