[APP][v1.8 (+US)] SGS3 Easy UMS - Mount external microSD card as USB mass storage

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:
?

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 ' '

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

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