app to sd card for android focusing on the Huawei S7

Note: this how to expects some unix or gnu/linux know how.

Things that need to be done before starting.

Have the Android SDK installed (or droidexplorer if you're on windows for adb, as I've got the sdk this howto uses adb on the command line.)

Root the device. This goes without saying, Z4Root is recommend.

Install busybox, this could be done by simple download a busybox installer from the android market

Step 1: Prepairing the SD card.

Note: I have an 8gb sd card, so my examples use this in mind.

Using which ever partitioning program you wish to use, create two partitions on your sd card.

Partition 1 is 7GB and is fat 32 formatted.
Partition 2 is 1GB and is not formatted (we will do this later on the device.)*

*in my case I've mucked up and my ext2 partition is only 400Mb

Now place the sdcard back into the device and boot.

We need to make an ext2 file system on the second partition. This is done via the command line on
the device. So fire up the adb shell

./adb shell

Type the command su to get root privilages, then type the following command:

busybox mke2fs /dev/block/vold/179:2

This will output some data. Once done on the second partition we now have an ext2 file system.

Once this is all done the SD Card is ready.

Step2: Mounting the card, and moving data to the card.

For this step we need to mount the /system partition as read write as this partition is normally
mounted read only. To do this run the following command:

mount -o rw,remount -t yaffs2 /dev/block/mtdblock1 /system
mkdir /system/sd

Then we need to mount the ext2 partition and we can do this via this command:

mount -t ext2 /dev/block/vold/179:2 /system/sd

We need to now copy the data from the data directory to the ext2 partition, as we want to preserve
permissions we're going to use the command tar (cp can preserve partitions, but I've had more issues
with cp not working correctly in busybox I prefer tar:

cd /data/
tar -cvf /system/sd/app.tar app
tar -cvf /system/sd/data.tar data
tar -cvf /system/sd/dalvik-cache.tar dalvik-cache

cd /system/sd

tar -xvf app.tar
tar -xvf data.tar
tar -xvf dalvik-cache.tar

rm *.tar

Step 3: scripts and cleanup.

To mount the ext2 filesystem at boot, we need two scripts. These both go into /system/etc

The first one is called install-recovery.sh and contains the following:

#!/system/bin/sh
#
/system/etc/init-sd.sh&

The next is called init-sd.sh and contains the following:

#!/system/bin/sh
#
MYLOG=/data/install-recovery.log
echo "$(date) Starting install-recovery.sh" > $MYLOG
echo "$(date) Waiting SD to become ready..." >> $MYLOG
sleep 10
mount -t ext2 /dev/block/vold/179:2 /system/sd 1>>$MYLOG 2>>$MYLOG
mount -o bind /system/sd/app /data/app 1>>$MYLOG 2>>$MYLOG
mount -o bind /system/sd/data /data/data 1>>$MYLOG 2>>$MYLOG
mount -o bind /system/sd/dalvik-cache /data/dalvik-cache 1>>$MYLOG 2>>$MYLOG
mount >> $MYLOG
echo "$(date) Finishing install-recovery.sh" >> $MYLOG

now you need to use a decent text editor (I like vi) on windows I reccomend notepad++

copy both of these into /system/etc

for example:

cp /sdcard/install-recovery.sh /system/etc
cp /sdcard/init-sd.sh /system/etc

Now we need to make sure these files are executable with the following commands:

chmod 755 /system/etc/install-recovery.sh
chmod 755 /system/etc/init-sd.sh

Finally, we need to remove everything in the existing /data/app /data/data/ and /data/dalvik-cache
with the following commands:

cd /data/app
busybox rm -rf *
cd /data/data/
busybox rm -rf *
cd /data/dalvik-cache
busybox rm -rf *

now you will notice some odd things happening on the screen of your tablet but that will be fixed
with the command:

reboot

and if all went well you now have all your applications on the sdcard.