While MicroSD card support was once very common for Android devices, most “flagship” devices today don’t include this. Many among the current batch of top-end devices– including the HTC One, Nexus 5, and Motorola’s X and G models lack MicroSD support. If you’re not comfortable with using cloud backup services for your device, our Plugable USB2-OTGTF can enable quick, on-the-go backup of photos or other content normally stored only on a device’s internal storage.
If you have an Android device lacking a built-in MicroSD card, have heart- the USB2-OTGTF and a couple of applications may help. If you’re a technical user who has a rooted device, your chances are better, however some very popular devices have applications enabling basic support for even novice users. For example, although Google’s Nexus 5 doesn’t have MicroSD support, adding it is relatively easy. Even for users without root access simply installing a couple of applications can enable access to a USB storage device like Plugable’s new USB2-OTGTF or basic devices like keyboards, mice, or other USB storage devices with low power demands.
To determine if your device supports USB Mass storage, first check if your device supports USB OTG mode. If it does, you may still need to install a second application to mount a storage device, and possibly a file manager if your device doesn’t already have one. To clarify, below are the features required for accessing files on a USB storage device on Android.
- Support for USB “OTG” host mode
For USB OTG checker, just launch the app and choose the option to “Check Device OS on USB OTG” and then press the check button. If your device supports USB OTG devices, you’ll see this message.
- Support for USB Mass Storage class devices
This is the level where a USB storage device is “mounted” to a location in the file system. Access to whatever file system is located on the USB device is either provided via OS-level drivers, or, if the app has root access, it can potentially add drivers for additional formats.
Disk Formats and accessing your files
The several USB OTG apps for Android include various levels of support for different disk formats. Recent Android versions typically support FAT and EXT3/4 out of the box, and may support read-only NTFS mode on some devices. NTFS write, HFS+, or exFAT will require other adding driver support for these additional formats, and may not be supported by all applications.
Once your device is mounted and formatted with a supported disk partition, to access files on the card, use your file manager of choice. Many android devices include one by default, however if your device doesn’t include one many are available on the Google Play store. ES file manager and Astro are popular, but many other good options exist.
Experimenting with different USB OTG applications for your particular device and format needs may be necessary, and your mileage is likely to vary on different devices. For most users, using the FAT format to do any transfer of files from an Android device is recommended since NTFS write and exFAT support are limited. For users needing to access files over 4GB from an Android device, read-only NTFS is the option most likely to be supported out-of-box.
Read on to find out how we’re able to access up to 32 GB of data on a FAT32/exFAT/NTFS formatted MicroSD card on the Nexus 5 (thanks to support for these file formats in the StickMount application) with the USB2-OTGTF.
Example Usage Scenario: Nexus 5
On our example Nexus 5 with root access on stock Android 4.4.2, using StickMount (free to try) is easy, and enables access to FAT, exFAT, and NTFS formatted storage, even when all three exist on the same storage device. The Nexus 5 supports USB OTG Host mode without any extra apps or work, as confirmed by USB Host Diagnostics.
For non-rooted devices, OTG Disk Explorer Lite supports FAT32 storage only, and is free. For only $2.49, the Nexus USB OTG File Manager adds NTFS read-only support.
For rooted devices, StickMount offers read/write access to FAT formatted volumes, and read access to NTFS volumes. On the Nexus 5, FAT and exFAT read and write seem to work automatically after installing StickMount– at least if BusyBox is installed. NTFS works in read-only mode, and seems to work in write mode after installing the NTFS3G driver– although some applications still try and use the in-box read-only NTFS driver and will fail when trying to write to the device.
We used ES file manager in our tests, but Astro, OI and other great options are also available.
Other Devices and Troubleshooting
With USB Host diagnostics, you need to have a USB OTG adapter and a regular USB device, or a USB OTG device physically handy. While USB OTG checker is a great option for finding quickly if a device supports USB OTG host mode, for troubleshooting we recommend USB Host Diagnostics. After launching the app, connect an OTG device and follow the prompts to find out what issues your device is having.
A working Nexus 5 shows support for everything but the Rooted API, so any failures indicate a layer to double-check. To begin, download USB Host Diagnostics, launch the app, and follow the instructions. After completion, you’ll see a report as shown in the screenshot below. 
Older Android devices may not have applications to enable USB Mass Storage support available, and that an application which works well on one device may not work as well on all others. Searching around for the best OTG storage applications for your particular device is recommended as a first step if you run into trouble. If you can only find OTG Storage applications for your device that require root access, it is likely that your device doesn’t support OTG host mode or a driver for a certain disk format.
In these cases the OTG mounting application has to install additional components to enable host mode– which requires root access. The very popular USB OTG Helper application’s developer maintains a list of devices known to work, or not work with USB OTG Helper.
When All Else Fails
In extreme cases when no application support for OTG storage devices is available, installing a 3rd party ROM like CyanogenMod (confirmed to support USB mass storage in both 10.4 and 11 builds on multiple devices) is a last resort. While 3rd party “ROMS” may boast newer Android versions and more features than those supported by the device’s manufacturers’ installing one will typically void the manufacturer’s warranty, and is likely to introduce it’s own unique issues.
Flashing a new ROM can be a frustrating experience for even for the most patient and advanced users, so proceed with extreme caution if you do decide to try replacing your “stock” Android build with something supported only by the good-will of the Android enthusiast community at large. Proceed with caution, at your own risk, and only if you can afford to lose access to the device you are trying to update if things don’t go as expected.