Android USB storage mount (Pendrives, External hard drives, Memory cards, etc)

Xperia the 2011 Sony Ericsson Xperia range support USB On-The-Go mode - this means that armed with the right adaptor your phone becomes a USB host, and lets you plug in devices such as mice, keyboards and game controllers.

The official way to use this is to buy a LiveDock Multimedia Station which the phone sits in, and gives you USB ports for connecting your controllers.  

However, the problem is that this isn't intended to be a mobile device - it’s a bit bulky to carry with you, and needs mains power.  Also, USB storage devices aren't actually supported.

If your phone is rooted, you can load a USB storage kernel module, and mount the storage device with a small (free) app.  

So, here’s what you need:

1. Root your phone.  
2. Get a Micro USB OTG Adaptor.
3. Find a suitable USB memory stick or SD card reader - it won’t work if it draws too much power.
4. Here’s how to check the power usage on Windows.

• Plug in your reader/memory stick into your PC/laptop.
• Start Device Manager, and open up the “Universal Serial Bus controllers” entry.
• Right click on each USB Hub, and check the “Power” tab until you find your connected reader/card.
• The power must be 200ma or less for it to work with your phone - here you can see an Integral USB SD Card Reader that requires 500ma, so doesn’t work (but that keyboard and mouse you see both work fine!) 

5. Download and install the Kernel Module loader app - this lets you load the additional usb storage module. [http://forum.xda-developers.com/showthread.php?t=1228605]
6. Download the kernel module (usb-storage.ko) and save it somewhere on your phone’s SD card.  Note that this is a specific module for Xperia phones - if you have a different phone, then try searching for a compatible usb-storage.ko [http://forum.xda-developers.com/showthread.php?t=1224676] [Terminal Emulator: https://play.google.com/store/apps/details?id=jackpal.androidterm&hl=en] [Module Loader: http://forum.xda-developers.com/showthread.php?t=1228605]
7. Download and install the Q5 USB Stick Manager - this is the app that will mount and unmount the USB device you connect. [http://android.gval.biz/]

You now have everything you need.  Here’s how to set everything up:

1. Run the Module Loader, select SD card modules, put a tick next to usb-storage.ko and click Save selection.  You should see a “successfully loaded” message.  You should only need to do this once, as the app will automatically reload the module when you restart the phone.
2. Put your SD card into your reader, plug the reader into the OTG adaptor, and plug the adaptor into your phone.
3. Run Q5 USB Memory manager app.  At the top, under “Please select block device” it should say something like “sdaX” If so, click the “Mount File System” button, and your device will be mounted.
4. Your files will be available under /usb_drive/ - you can use a root compatible file browser to browse this folder, and do whatever you need.
5. When you're finished, run the memory manager again, and press Unmount - you’ll then be free to unplug your device.

For more info:

http://forum.xda-developers.com/showthread.php?t=1224676

http://forum.xda-developers.com/showpost.php?p=19919167&postcount=2