[Galaxy S III Themes and Apps] gumpelstilzchen:
This app will make the external (not the internal!) microSD card of your Samsung Galaxy S3 (International, US versions, International LTE) available as USB mass storage device.

Also reported working on Galaxy Note 2, see compability list below.

Most important commands in this app:

http://xdaforums.com/showpost.php?p=27282116&postcount=58

http://xdaforums.com/showpost.php?p=28151372&postcount=133

http://xdaforums.com/showpost.php?p=28670285&postcount=1

Thanks d4fseeker :good:

:angel: If you like the app, please consider donating by buying this app or via PayPal (see link on the left, below username etc.) :good: Some people gave 1 star reviews to the app although I think I'm extremely clear with stating that this is only a donation app - but I can't change that :(

Compability

MODEL / ROM / KERNEL / APP VERSION / CONFIRMED BY

WORKING:
GT-I9305 (LTE) / ? / ? / 1.8 / Jarmezrocks
SGH-I317 (AT&T Note 2) / I317UCALJ2 / ? / 1.8 / dabuck
GT-N7100 (Intl Note 2) / ? / ? / 1.8 / geovass
GT-I9300 (International) / Stock (LFB) / Stock / 1.5 beta / woaloo
GT-I9300 (International) / CM10 / ? / 1.5beta / lubluchka
SGH-I535 (VZW) / ? / ? / 1.4beta / open1your1eyes0
SGH-T999 (T-Mobile US) / ? / ? / 1.4beta / gr4p3s
?

NOT WORKING:
?

I can only test it on my own GT-I9300; please report back your success with the information needed in the table above.

If you have a custom kernel, you have to make sure there is one of the three possible lun files available (see Problems section).

Regarding US versions: Starting with 1.4beta, it also works with US versions (see here). This may not be the case for all variants, so please report back with the information needed in the compability table.

Problems? Not working?

Report the exact problem, model/ROM/kernel/etc., the exact error message and the results of the following commands (use Terminal Emulator or something similar):

mount

ls /sys/devices/platform/s3c-usbgadget/gadget/lun0/file
ls /sys/devices/virtual/android_usb/android0/f_mass_storage/lun_ex/file
ls /sys/devices/virtual/android_usb/android0/f_mass_storage/lun/file

mount | sed 's/ on / /g' | grep extSdCard | cut -f 1 -d ' '

Note: Only ONE of the three ls commands must be successful (file exists)

You may need to replace "extSdCard" in the last command with the mount point name of your external sd card (e.g. external_sd or sdcard1 for CM10)

If the last command does fail, there is probably something wrong with your BusyBox installation. You should reinstall it - I recommend this app.

On some Win7 PCs, these steps may be needed:

Get the "extSdCard is being accessed by [...]" message? Wait until the app accessing the sd card has finished, stop it yourself or reboot.

Changelog

1.8
- added support for third lun file, should work with GT-I9305 (Intl LTE version) now

1.7
- fixed recognition failure if "mount" output contained "on" as the second column (e.g. Siyah kernels)

1.6
- fixed code so that it (hopefully!) works with recent CM10 versions again
- made some error messages clearer
- drop of "beta" name doesn't actually mean much by the way, but I think it looks a bit cleaner this way and does not make a difference

1.5beta
- added support for CM10 sd card paths (/mnt/external_sd and /mnt/sdcard1)

1.4beta
- added alternative method for users without s3c-usbgadget (may work on US versions)

v1.3beta
- rewrote the whole logic
- now opens Play Store entry of BusyBox if it is not yet installed
- notifies user if device seems to lack s3c-usbgadget module
- notifies user which apps are accessing the extSdCard
- generally better and more precise error messages

v1.2beta2
- added info about busybox requirement (maybe this will be removed later)
- added link to donation app

v1.2beta
- Automatically tries to unmount extSdCard before starting UMS mode. This will fail if some app is accessing it, so just wait or cancel that app if you know it and try again - possibly several times. This prevents the potential data loss with previous versions.
- It now checks the location of the extSdCard device. This should help with compabilty, e.g. for US versions.
- Added some log output and toasts (2s delay)
- Added link to this thread and version number in app
- It's a beta so please beware, but I think the worst probable thing that can happen is that it does not work (e.g. it does not start UMS if it cannot unmount the extSdCard).
- Dammit, the whole day is already over

v1.1
- Added option for going back to MTP

v1.0
- Initial release

Download

v1.8: http://dl.dropbox.com/u/22760184/android/sgs3-easy-ums/SGS3-Easy-UMS-v1.8.apk

v1.7: https://dl.dropbox.com/u/22760184/android/sgs3-easy-ums/SGS3-Easy-UMS-v1.7.apk

v1.6: https://dl.dropbox.com/u/22760184/android/sgs3-easy-ums/SGS3-Easy-UMS-v1.6.apk

v1.5beta: https://dl.dropbox.com/u/22760184/android/sgs3-easy-ums/SGS3-Easy-UMS-v1.5beta.apk

v1.4beta: https://dl.dropbox.com/u/22760184/android/sgs3-easy-ums/SGS3-Easy-UMS-v1.4beta.apk

v1.3beta: https://dl.dropbox.com/u/22760184/android/sgs3-easy-ums/SGS3-Easy-UMS-v1.3beta.apk

v1.2beta2:

https://dl.dropbox.com/u/22760184/android/SGS3_Easy_UMS_v1.2beta2.apk

v1.2beta: https://dl.dropbox.com/u/22760184/android/SGS3_Easy_UMS_v1.2beta.apk

v1.1: http://dl.dropbox.com/u/22760184/SGS3_Easy_UMS_v1.1.apk

v1.0: http://dl.dropbox.com/u/22760184/SGS3 Easy UMS.apk

(also, it's attached)

Credits: d4fseeker, Sakaschi, bazald, dAKirby309 (icon), RootTools devs

Uses RootTools project, which is made available by Stephen Erickson,
Chris Ravenscroft, Dominik Schuermann, Adam Shanks under Apache
License Version 2: http://www.apache.org/licenses/LICENSE-2.0