How to Mount a Flash Drive on Your Android Device

Why Do I Want To Do This

Even if your Android device has a micro SD slot, and not all devices
do unfortunately, it’s still inconvenient to remove the SD card to load
it up with content or transfer files (especially if you have apps that
rely on SD card storage). It’s also inconvenient to tether your device
or wirelessly transfer the files, especially for files that you may not
need to store inside the phone on the internal storage or SD storage.
If you want to bring a bunch of movies on a trip to watch on the
plane or in your hotel, for example, you really don’t need to clutter up
your internal storage options with bulky media files. Instead, it’s
much easier to just throw files on a cheap and spacious flash drive and
then mount the flash drive when you want to watch the movies, unload
media you’ve created on the phone to free up space, or otherwise enjoy a
multi-gigabyte storage boost.
Rare is the Android device that comes with a full size USB port,
however, so you’ll need a little techno-wizardy to make it happen. Let’s
look at what you need and how to check if your device supports the
required equipment.

What Do I Need?

The magic that makes it possible to mount a regular USB flash drive
on your Android device is a a USB specification known as USB On-The-Go
(OTG). The specification was added to the USB standard way back in 2001
but don’t feel bad if you’ve never heard of it. Although the
specification is over a decade old now it wasn’t until Android 3.1
Honeycomb (released in 2011) that Android natively supported OTG.
The most important element of the OTG specification is that it gives
Android the ability to specify whether it is the master or the slave
role when connected to a supported device. In other words even though
the general role of your Android device is to be the slave (you attach
it to your computer via a data sync cable and your computer acts as the
host) the Android device can be the host thanks to OTG and storage
devices can be mounted to it instead. That’s the most important element
as far as our tutorial is concerned but If you’re curious about the OTG
specification in a broader sense you can check out the USB On-The-Go Wikipedia entry here.

A Phone That Supports OTG

Unfortunately, just because the specification is well established and
Android has supported it for years doesn’t mean that your device
automatically supports it. In addition to the required Android kernel
component and/or drivers, there needs to be actual support by the
physical hardware in your phone. No physical support for host mode via
OTG, no OTG goodness.

Testing to see if your phone supports OTG is really easy, however, so
don’t be discouraged. In addition to looking up the specs for your
phone via search engine query you can also download a helper
application, like USB OTG Checker, to test your device before investing energy into the project.
Note: It is possible to have a device that can support OTG
on the hardware-level but that does not have the proper kernel/drivers
for software-side OTG support. In such cases it’s possible to root a
device and install drivers, flash a new ROM with OTG support, or
otherwise remedy the situation, but those courses of action are beyond
the scope of this particular guide and we note them simply so readers
inclined to engage in such advanced tinkering know it’s a possibility.
We recommend searching the excellent XDA-Developers forums for your phone’s model/carrier and the term “OTG” to see what other users are doing.

An OTG Cable

If your device supports OTG then it’s just a simple matter of picking out an OTG cable. OTG cables are dirt
cheap, by the way, so don’t worry about breaking the bank. Although you
can get OTG cables with all sorts of bells and whistles on them (SD
card reader slots, etc.) we wouldn’t bother with the extras as it’s just
as easy to plug in the devices you’re already using on your regular
computer into a plain old dirt-cheap OTG cable.
In fact, the only real decisions to be made when it comes to OTG
cable shopping are: whether you want to wait a month on shipping from
Hong Kong to get the cheapest one possible and whether or not you want
an OTG with charging capabilities.
If you’re willing to wait on shipping, you can pick up a non-powered OTG cable
for, we kid you not, $1.09 with free shipping. You’ll wait a few weeks
for it to get sent parcel post from Hong Kong but it’ll cost you less
than a truck stop cup of coffee. If you want a non-powered OTG cable
right now, you can pick up this model for $4.99 with free Prime shipping.
If you plan on doing some serious media watching on your device using
an OTG mounted flash drive, we’d recommend picking up an OTG cable with
a power-passthrough so you can use a standard charging cable to pump
juice to your device while you’re catching up on your favorite shows.
Again, if you’re in no rush you can pick up a powered OTG cable for $1.81. If you want it right now, you can pick up a similar model for $4.99 with free Prime shipping.

A Flash Drive

The final thing you need is a simple flash drive or other USB media
(an external powered portable hard drive, an SD card in an SD card
reader, etc. will all work). The only critical thing is that your flash
media is formatted in FAT32. For the purposes of this tutorial we’re
using the sturdy little Kingston Digital DataTraveler SE9 but any properly formatted and functioning drive will do.

Mounting the Drive

Just like with our How to Connect Your Android Phone to Your TV
guide, the hardest part is checking your hardware and buying the right
cable. Once you have the right hardware and the right cable, the
experience is pure plug and play goodness.
Plug the OTG cable into your Android device (if you have a powered
OTG cable, connect the power source at this time too). Plug the storage
media into the OTG cable. You’ll see a notification in your notification
bar that looks like a little USB symbol. If you pull the notification
drawer down you’ll see a notice that there is now an attached USB
storage option. You don’t have to do anything at this point as the drive
is already mounted and available to Android.
If you do tap on the notification (or navigate to Settings ->Storage) you can take a closer look at the USB storage options.

When you’re done with the flash storage, this is the menu you want to
visit in order to use the “Unmount USB storage” option to properly
unmount and remove your media.

Otherwise, feel free to jump right into using the removable media.
You can browse the file structure in the native Android file browser or
your file browser of choice, you can copy files to and from the device,
and you can watch any media stored on it.
Here is our flash drive as seen in the drive-selection menu in ES File Explorer, listed as “usbdisk.”

And here’s a screenshot of our file transfer test using the same file explorer.

File transfer is snappy as is media playback. Thanks to OTG we no
longer need to crack open the case of our device to get at the micro SD
card or play any advanced games balancing the storage load on our
internal memory. For the dirt cheap price of an OTG cable and a big
flash drive we can instantly expand our storage (and easily swap it
out).