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

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Thanks Meter: 381
By Kopfgeldjaeger, Member on 15th June 2012, 12:18 AM
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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:

Thanks d4fseeker

If you like the app, please consider donating by buying this app or via PayPal (see link on the left, below username etc.) 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


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

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):

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:

Now follow these steps:

1. On your Windows 7 computer you will see it will try to install “SAMSUNG Mobile MTP Device” as one of the drivers and fail *this is normal*
2. Go into Device Manager on your computer, right click “SAMSUNG Mobile MTP Device” and select “Properties”
3. Click on the “Driver” tab and click the “Update Driver” button, a prompt will then come up
4. Select “Browse my computer for driver software”, then select “Let me pick from a list of device drivers on my computer” on the next screen
5. Select “USB Mass Storage Device” as the new driver from that list and finish up that install
6. At the end you will see something like this on your computer – Screenshot Here
7. Windows will install final drivers automatically and a new “Disk drive” will show up on your computer, this is your external SD card on your device

Keep in mind that it is not possible to get access to the internal storage as USB mass storage device.

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

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

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

- 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

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

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

- 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

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

- 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

- Added option for going back to MTP

- Initial release










(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:
The Following 355 Users Say Thank You to Kopfgeldjaeger For This Useful Post: [ View ] Gift Kopfgeldjaeger Ad-Free
15th June 2012, 01:05 AM |#2  
whiskeybro's Avatar
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Sent from my GT-I9300 using xda premium
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15th June 2012, 06:17 AM |#3  
cmd512's Avatar
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Confirmed working, thanks!
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15th June 2012, 06:50 AM |#4  
beautyangel's Avatar
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Orion Galaxy
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Thumbs up hard work, great result
nice touch buddy. thanks dude. +1
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15th June 2012, 07:58 AM |#5  
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Dude, any way to reverse this? It screwed up my comp and phone...
15th June 2012, 08:11 AM |#6  
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Sent from my GT-I9300 using XDA
15th June 2012, 08:19 AM |#7  
BoneMo's Avatar
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Originally Posted by makimo2989

Dude, any way to reverse this? It screwed up my comp and phone...

what happened to phone and computer ??
15th June 2012, 08:25 AM |#8  
Thanks Meter: 2
Working perfectly here as well

15th June 2012, 08:49 AM |#9  
SlimJ87D's Avatar
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This sounds awesome. Does it increase transfer speeds?
15th June 2012, 09:06 AM |#10  
kultus's Avatar
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unbelievable!!! It it possible to see also internal storage as well? In explorer I get 2 new devices one is SD card and the second I cant access...
15th June 2012, 09:08 AM |#11  
SlimJ87D's Avatar
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How about your MicroSD card, does it mount that too?
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galaxy s3, mass storage, sgs3

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