[Eee Pad Transformer General] sidneyk:
At the request of others, I have decided to write this guide pertaining to ROM customization. I found that in most of the current custom Jelly Bean ROMs for the TF101, that the GPS configuration has been changed, at least compared to the stock Asus ICS ROMs for the TF101 and the stock Asus Jelly Bean ROM for the TF300T, and they are using modified user / group and permissions settings. They all say that it is because those items have changed in Jelly Bean. They are also using a custom /etc/gps.conf file. The problem is that I, along with several others, aren't seeing very good GPS response and some claim not to see any. The ones that do see something, see that the first initialization takes forever and then is likely to not hold a fix, only seeing a few satellites. I made some changes in the ramdisk and /etc/gps.conf file and tested with a few of the Jelly Bean ROMs for the TF101 and found that settings matching the stock Asus settings performed quite well and was asked to share the process that I used. While it would be easier probably to just post the modded kernels for others to reflash, I'll give it a go at explaining what I've done.

1) This guide will require either a working native Linux install or can probably be used with a virtual machine Linux install. I'm using Ubuntu 12.04-x86_64 LTS as Ubuntu is usually used in most of the guides I've found. You may be able to make things work with other Linux flavors, but YMMV. I'm going to assume, at least, a basic knowledge of Linux file systems and the ability to copy and paste to a terminal and follow instructions.

2) You may need to install the Android SDK and at least one platform in order to get a working "adb" command, which will be needed. You may be able to get the "adb" binary from other sources that will work and "adb" will require some setup in udev rules to allow your normal user to access the tab with it. I'm going to assume that you have all of these things in place and working and that "adb" is in your path. If not, then Google is your friend.

3) For good measure, it would help and definitely won't hurt anything to have some build environment files in place. In a terminal, copy and paste the following:

sudo apt-get install git-core gnupg flex bison gperf build-essential zip curl libc6-dev libncurses5-dev:i386 x11proto-core-dev libx11-dev:i386 libreadline6-dev:i386 libgl1-mesa-glx:i386 libgl1-mesa-dev g++-multilib mingw32 openjdk-6-jdk tofrodos python-markdown libxml2-utils xsltproc zlib1g-dev:i386

Let that install and when it is finished, copy and paste the following:

sudo ln -s /usr/lib/i386-linux-gnu/mesa/libGL.so.1 /usr/lib/i386-linux-gnu/libGL.so

4) Now we need to grab dsixda's Android Kitchen, which is where some of the magic can happen. Go here to read up on how to use it and to find the download link. While the TF101 isn't specifically supported, there are a lot of things that we can still use it for. Just don't try to build a ROM and flash it with this before you have read dsixda's thread thoroughly or you may wind up with a brick. I'm only going to describe things that I've done and tested and that I know will work. For ease of this guide, I'm going to assume that you read the instructions there and that you unzip the downloaded file to "/home/'yourname'/android/kitchen/".

http://xdaforums.com/showthread.php?t=633246

5) Now we need to build the blob tools used to pack and unpack the .blob files. Here we will download the source code for these tools and build them on the local machine. Go here:

https://github.com/AndroidRoot/BlobTools

6) Download the .zip file and extract to "/home/'yourname'/blob_tools/", where 'yourname' is your home directory name. Then, in a terminal, type "cd ~/blob_tools", without the quotes. Then type "make". When this is finished, type "mkdir ~/bin", if it doesn't already exist, and then type "cp ./blobpack ~/bin/;cp ./blobunpack ~/bin/". Now we need to make sure that "~/bin/" is in our PATH. Type "cat ~/.profile" and make sure that there are lines matching the below there:

# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
PATH="$HOME/bin:$PATH"

If not, use an editor like gedit, to add them just before the last line which should say "fi". For basic instructions on the blob tools, see here:

http://xdaforums.com/showthread.php?t=1068548

That should be all for the tools and setup. Now reboot your PC to Linux, for good measure.

I'm going to use as an example, the changes I made for the GPS permissions and settings. Anything else will be up to your own personal study and research and experimentation. I assume no responsibility if you do something mentioned here or not or if you should brick your device.

1) Download the CWM flashable custom ROM of your choice. I'm not going to deal with Asus stock ROMs here because there are extra steps to do to look into those completely. Extract the ROM to a directory under your home directory. You will have to create it, such as "Team_EOS3" or whatever. I'm going to use the graphical file manager Nautilus and the graphical text editor gedit to work with files and directories and to edit files. When using Nautilus be sure to go to the "View" menu and select "Show hidden files". Some work will also be done in a terminal. I use Gnome terminal.

2) For example, I have a folder "K900_AOKP_JB", where I extracted K900's ROM. So if I look at that in Nautilus, I see 2 folders, "META-INF' and "system" and 2 files, "boot.blob" and "boot.img". Most of the custom roms will not have the boot.img file, only the *.blob file. The blob file and the boot.img file should be the same thing. Each contains the compressed kernel image and the initial ramdisk.

3) From a terminal, type, for example, "cd ~/K900_AOKP_JB". Then type, "blobunpack ./boot.blob", substituting the appropriate names for your particular files. In Nautilus, you will see that 1 more file was created, in my case, "boot.blob.LNX". Right click and copy this file to your Kitchen WORKING_DIRECTORY which you should have created from following the kitchen instructions. For me it is "~/android/kitchen /WORKING_091312_142859/", where "~" is shorthand for "/home/'yourname'", i.e. your personal home directory. Right click and delete or move to trash the boot.img file that is there already. Right click the file you just copied, i.e. "boot.blob.LNX" and rename it to "boot.img". Upper and lower case matters, so pay attention.

4) From a terminal, type "cd ~/android/kitchen". Then type "./menu". Choose option "0", then choose option "20", then choose option "w". Follow any instructions that come up. These actions will create a new directory, "~/android/kitchen/BOOT-EXTRACTED/", which is where the kitchen just extracted your renamed blob file (boot.img). Inside, you will see a "boot.img-ramdisk" folder, which contains the ramdisk files and a "zImage" file, which is the compressed kernel.

5) Inside the ramdisk folder, we are going to edit only the "init.ventana.rc" file to change some GPS settings. Open the file with gedit and scroll down to the #GPS section. Change it to read the following:

# GPS
mkdir /data/gps
chown system system /data/gps
chmod 770 /data/gps
chown root system /dev/ttyHS1
chmod 0664 /dev/ttyHS1

Scroll down to the #GPS init section and change it to read the following:

# GPS init
write /sys/class/gpio/export 203
write /sys/class/gpio/gpio203/value 0
write /sys/class/gpio/gpio203/direction out
chown root system /sys/class/gpio/gpio203/value
chmod 0664 /sys/class/gpio/gpio203/value

Scroll down to the # Start GPS daemon section and change it to read the following:

# Start GPS daemon
on boot
service gps-daemon /system/bin/glgps -c /system/etc/gps/gpsconfig.xml
user root
group root
class late_start

Save the file. Right click and delete "init.ventana.rc~", which will only show up if you selected to "Show hidden files" in the "View" menu. In Nautilus move back to your kitchen WORKING directory.

6) In the terminal that should still be running the kitchen menu, choose option "b" to rebuild the boot.img. You can now exit out of the kitchen menu. Back in Nautilus, right click and rename the "boot.img" file to "boot.blob.LNX" or whatever your original extracted blob file was called. Right click and copy to the folder where your ROM was extracted. Choose to replace the original file if asked.

7) In a terminal, type "cd ~/K900_AOKP_JB", substituting "K900_AOKP_JB" with whatever your extracted ROM folder is called. Then type "blobpack ./boot.blob LNX ./boot.blob.LNX", substituting your file names for "boot.blob" and "boot.blob.LNX".

8) In Nautilus, in the folder where your ROM was extracted, double click the "system" folder, then double click the "etc" folder. Then double click the "gps.conf" file. It should open up in gedit, if you were using that before, if not then choose to display it. Change it's contents to read the following:

#
# IMPORTANT:
# this file is only used by NetworkTimeUpdateService.java
# DO NOT make any GPS related settings here.
#
NTP_SERVER=xtra1.gpsonextra.net

Save and close the "gps.conf" file.

9) In Nautilus, in the folder where your ROM was extracted, left click on the "META-INF", "system" folders and the *.blob and boot.img file, if present, while holding down CTRL key, to highlight all 3 or 4 items. Right click on 1 of the highlighted items and choose "Compress". Rename the file if desired, especially if you have the original zip in that folder by the same name and want to preserve it, and then click "Create". The new zip file, with your custom name, will be created in the same folder after a few seconds. In my case, I chose to name it "K900_AOKP_JB-test.zip".

10) You now have created your own customized version of someone else's ROM, modified for your needs or experimentation. Now it's time to push it to your device. You can use Dropbox, if desired to do this, but the easier way is to use adb. I'm going to assume that you have a working Custom Recovery, preferably one that can read both internal sdcard and external MicroSD and that you have adb setup and working.

11) Plug your charging cable into the computer first and then plug the other end into the TF101.

12) In a terminal, type "cd ~/K900_AOKP_JB", substituting "K900_AOKP_JB" with the folder name where you extracted your ROM and where the new zip file resides. Type "adb devices" and after a second or two, you should see something similar to the following:

* daemon not running. starting it now on port 5037 *
* daemon started successfully *
List of devices attached
03806245421f9417 device

If you get something looking like that, then adb is working.

13) In the same terminal, type "ls", which will list all the files and folders in your extracted ROM directory (or whatever your current directory is). If your recovery can read only the internal sdcard or both, then you can type "adb push ./K900_AOKP_JB-test.zip /sdcard/Download/", substituting "K900_AOKP_JB-test.zip" with whatever you named your zip file. After a few minutes you should get a confirmation that the transfer completed and can verify that it did with a file manager on the device.

14) If your recovery only reads from the external MicroSD card, then type "adb shell", then type "ls". You will get a list of all files and folders in the root directory of your device's file system. If you are running ICS or older, then you should see a "Removable" directory. If you are running one of the custom JB ROMs, then you may not have the "Removable" folder, but most likely a "storage" folder. For ICS or older, your external MicroSD should be located at "/Removable/MicroSD/". In the latter case, it should be located at "/storage/sdcard1/". In any case, once you have verified where the external card is mounted, then type "exit". Now type either "adb push ./K900_AOKP_JB-test.zip /Removable/MicroSD/" or "adb push ./K900_AOKP_JB-test.zip /storage/sdcard1/", depending on your results from adb shell. After a few minutes you should get a confirmation that the transfer completed and your new zip should now be on the root directory of your external MicroSD card.

15) Now you should be able to reboot to your recovery and flash the zip you created just like you would flash any ROM. Reboot and enjoy, from this example, working as intended GPS.