I had an HTC desire phone, before upgrading to a Galaxy S4 Mini.

I have run into an annoying problem. On my phone (not on the SD Card), I have private data, including an RSA key, which I use to SSH into my different computers and servers. On the Desire S, I had the phone on default "Charge only" so people who nicked my phone didn't just get access to what was on it.

How do I do something similar with the Galaxy S4? I need some way to disable the mount-by-default so people who steal my phone can't just plug-in a USB cable and steal all my data. The phone should still be able to mount as a storage device, but ONLY when it is specifically activated.

In screen-locked mode, it still auto-mounts when plugged in - not exactly a good way to protect the data on the device.

  • On Android 4.1+ (possibly from 4.0), as it now uses MTP, it automatically mounts. I haven't found a way around this yet, short of having a ROM that allows you to use normal USB connection.
    – Liam W
    Jul 17 '13 at 18:32
  • On JB, if accessing via USB, the handset is prompted to accept/reject the host's public key (RSA key), in short, have not seen nor heard of a way to prevent auto-mounting, even activating Developer's settings and enabling usb debugging...
    – t0mm13b
    Jul 17 '13 at 18:46
  • Isn't there some USB Connection settings in Settings->More? If not, maybe it's simply hidden. Using e.g. Apex Launcher, long-press empty space on homescreen, select Shortcut->Activity let's you browse all activities of all apps. Check the Settings app here, try what sounds promising (don't worry if some items simply "force-close", simply try the next). This way I was able to e.g. access the SIP settings which were hidden on my LG Optimus 4X.
    – Izzy
    Jul 18 '13 at 7:04

I don't know if this applies to the S4 but on my Nexus devices it shows up on my pc as a 'drive' but I can't access anything until the phone is unlocked (the normal screen lock - pattern/pin). If you have a screen lock set it shouldn't allow access to the device until you unlock it.

  • That is actually true. There is no way to access the files while the phone is locked. Jul 25 '13 at 10:02
  • 1
    This is not true on the Galaxy Note series which is very similar to the S series. It is also not true on the S3, so I would imagine (though have not tested) that it is the same for S4. Jun 2 '14 at 15:38
  • @JoelEtherton Same on s5. I assumed it was a Samsung vs HTC problem. Disabling Autoplay and Autorun in Windows 7, with the s5 screen locked, it still auto-mounts the drive. I am unable to clear the MTP checkbox on the phone, the only way to clear it is to check the PTP.
    – Damon
    Jun 4 '14 at 15:56
  • Do you have a password/pin/pattern lock (not just a swipe)? If so I think it should prevent access to the device until it's unlocked. If you only have a swipe/no lock screen then the phone is already 'unlocked'. I don't have a Samsung device to check this on but it seems like a massive security flaw if the device is accessible without unlocking.
    – bmdixon
    Jun 4 '14 at 16:01

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