This is a hack that that allows you to swap internal storage with your external SD card so you can increase your app data storage.
All credits go to original i9300 App2ExtSD Hack by mattiadj. I simply hacked it to work with U.S. versions and also I’ve added code so it will disable this feature when you don’t have a microSD card inserted (app storage will default to internal when no microSD card is inserted).
E.g. If you have 16GB internal storage on Galaxy S3, you can install this witih a 64GB microSD card and swap the storage and get 64GB on your app storage instead of 16GB.
Before you can use this, you will need:
1) Rooted Galaxy S3 (SCH-I535/SPH-L710/SGH-T999/SCH-I747) or also Canadian versions too (i747m, etc…etc…)
2) A ROM/kernel with init.d support!
3) I’ve only tested this with TouchWiz-based ROMs, so it should work on stock ROMs and any TouchWiz-based ROMs, not sure on CM9 or CM10.
4) You must use the FAT32 or EXTFAT zip file below, depending on what format your microSD Card is in! (e.g. if you have a FAT32 microSD card, use FAT32)
v0.2 One script works for both FAT32 or EXTFAT.
v0.1 Added script to only enable when microSD inserted.
To get this working, downloadna dn simply flash the zip files in your CWM Recovery:
Download for v0.2
Q: The script isn’t working for me, I think my ROM doesn’t support init.d!
A: You can also use Script Manager from the Play Store, find the file /system/etc/init.d/11extsd2internalsd and enable “root” and “boot” on any rooted phone.
Q:How to disable this?
A:If for some reason you are having trouble, simply delete /system/etc/init.d/11extsd2internalsd.
if you leave your microSD card out during boot (then re-insert it after), your phone will work as normal (internal storage used for app data).
Q: What if my ROM doesn’t support it, will it mess up my phone?
A: No, if your ROM doesn’t support init.d scripts, the script will simply not run and nothing will happen.
Q: Will it mess up my microSD card if I don’t know it’s a FAT32 or EXTFAT and try this?
A: No, it will simply not work if your microSD card is not in FAT32 or EXTFAT format.
Q: How do I know my microSD card is FAT32 or EXTFAT?
A: If you have a microSD card adapter, insert into your computer and do right-click and “properties” for Windows. For Mac or Linux, it should be similar, try googling it.
Here’s a quick video demo: