Many Android phones come with very little storage, of which the operating system already consumes around 6GB. Fortunately, phones with Android 6.0 Marshmallow or later can expand their storage in a snap. But a few problems can make using expandable storage difficult.
4 Problems With microSD Cards
Unfortunately, using microSD cards on Android comes with issues.
First, buying a card can be a problem. Multiple microSD card certifications and standards can confuse consumers (e.g. FAT vs exFAT). The amount of jargon bewilders, so I’ll try to break the subject down into its most important parts: you need to correctly format the card and choose one that’s as fast as your system permits.
Second, microSD cards need configuration. If you simply stick a card in a phone, it won’t necessarily move all your files over onto it. First-time use of a microSD card may require manually transferring apps and files.
Third, you can’t use a microSD card in a computer and smartphone. Android 6.0 Marshmallow (and newer) prevents users from swapping their card between computers and using it as external storage (unless you know a certain trick).
Fourth, creating a backup of microSD cards on Android 6.0 or newer is a pain. Unfortunately, no easy answer exists. In the short term, if you want to migrate from a smaller card to a larger one, you don’t have any good options in Android 6.0 or later.
1. Buy the Best microSD Card
Unless your phone includes a microSD card slot, you’re out of luck. However, if your phone is compatible and you want a microSD card, know the kind of card you need. Find two things: one, how large a microSD card your phone can handle and, two, the fastest card for your needs.
microSD Card Size and Speed
microSD cards fall into three capacity classifications. Two of these are still used on Android devices: Secure Digital High Capacity (SDHC), and Secure Digital eXtended Capacity (SDXC). SDHC covers cards under 32GB, and SDXC covers cards between 64GB and 128GB. In general, phones more than five years old probably use SDHC, while newer phones tend to use SDXC.
When picking a size, first find out the maximum size your phone can handle (that’s probably SDXC, or larger than 32GB) and estimate the amount of storage you need. Buy a capacity that is twice or 75 percent more than you need. A mostly filled card runs slower than an empty one.
After picking a card size, you need to choose a speed. The two most common certifications relevant to Android are UHS-I and Class 10. Some have argued that UHS-I is a faster standard than Class 10. When tested, though, the differences appear trivial:
For storing media files, the two standards are about equal in performance. However, if you plan on throwing apps on the card, look for a rating called app performance class, designated by an “A” rating followed by a conjoined number. Here’s a YouTube video explaining the certification:
The standard is (as of 2017) relatively new and only a handful of SanDisk microSD cards feature an A1 rating (there’s also a UFS rating, but there don’t seem to be any cards with it yet). Here’s an example of what an A1 rating looks like on a card:
A-Certification Is Deceiving and Uncommon
Unfortunately, the A1 standard is both deceiving and uncommon. What’s deceiving is that some cards without the certification perform like A1-rated cards. For example, The Wirecutter and Jeff Geerling published data showing that Samsung’s EVO+ cards had performance almost equal to the SanDisk Extreme Pro.
It’s uncommon because only two SanDisk cards are A1 rated. And that’s likely because the organization which governs the SD Card standard charges money in exchange for a rating. In reality, many other cards meet the criteria of the A1 certification.
So What Type of microSD Should You Get?
It depends on the kind of data you use. If it’s only music or video files, the ubiquitous Class 10 or UHS-I certification is good enough. Anything more than that wastes money — unless you’re using the card alongside a digital camera with 4K capabilities (the difference between 4K and Ultra HD).
For use with applications, the Samsung EVO+ or Select offers the best performance-per-dollar. Just make sure you have Android 6.0 or newer.
- Samsung EVO+ and Samsung EVO Select: These are the same card. Both are equipped with lower endurance TLC NAND packages (why TLC has problems). But offer the best performance and capacity relative to its price.
- SanDisk Extreme Pro: SanDisk’s Extreme Pro uses high-endurance MLC NAND packages, which means it’s around twice as reliable as TLC microSD cards. And it’s a bit faster than its nearest competitors, but it costs more.
- SanDisk Plus: While it has an A1 rating, it’s not as fast as either the Extreme Pro or the EVO+. The trade-off? It costs less than either the EVO+ or SanDisk Extreme.
- SanDisk Ultra 400GB: The Ultra uses 3D TLC NAND (which is extremely durable). It’s also the largest capacity microSD card available as of 2017. However, the price is outrageously high and the performance is less than the Extreme Pro.
2. Format and Configure Your microSD Card
Devices running an Android version below 6.0 Marshmallow require no further steps than partitioning the microSD card, which the system does for you. Android 6.0 and newer include special integration with the microSD card, which makes moving all the apps and data easy.
Formatting Your microSD Card
After getting a microSD card, you have to format it. Fortunately, after inserting a microSD card into an Android handset, the system automatically offers to format your storage. It’s simple.
However, Android does not automatically move apps to the card. To make a microSD card your primary space for holding apps, navigate to Settings > Storage. Then select your internal SD card as the Default write disk.
If the card is unformatted, you’ll need to do so manually. First, from the Storage settings menu, choose your external card by tapping on it. Once selected, tap on the three dots in the upper-right side of the screen. From the context menu, choose Format as internal (forgive the screenshot, my storage is already formatted as internal).
You can also choose to Migrate data from your internal storage to the microSD card. If you choose this option, the operating system will begin copying apps from your internal storage to the card. Note, though, that it will not copy system apps or apps with administrator privileges.
3. Partition Your microSD Card
On top of the issues with differing card sizes and speeds, even the latest versions of Android don’t properly use microSD cards. Fortunately, it’s possible to partition (separate) a microSD card into internal and external storage.
Doing so resolves the issue with being unable to transfer data (like media files) to and from the card. It also allows Android to encrypt sensitive portions of the card, making it unreadable to malicious third parties.
Formatting Your microSD Card as Internal and Removable
Thanks to XDA Senior Member Octanium91, you can now format a microSD card as both internal and external. This is particularly useful for those using custom ROMs, those moving media files between their computer and their microSD card, and, well, pretty much everyone. While this method works great, it, unfortunately, comes with some requirements.
First, you need to know how to connect to a phone using the Android Debug Bridge (ADB). I’ve tried to explain how to properly set up ADB. However, many users report never being able to successfully use ADB. You were warned. Second, you need a phone that supports microSD cards.
Second, connect your smartphone to your computer (with either a USB-C or microUSB cable).
Third, on a Windows computer, run aftiss.cmd from the downloaded files. Note that Linux users instead use aftiss.sh instead of the CMD file.
Fourth, choose one of four formatting modes. Be aware that each comes with its own advantages and disadvantages. My personal recommendation is to set the card at 25% SDCard and 75% Internal. It allows you a small amount of space for moving internal files around and a large amount of space for apps. Most media hoarders will probably be fine with keeping the card entirely as SDCard storage (portable storage).
After finishing the format, you can move the card to a computer and transfer files to the SDCard partition.
Benefit From Fast Expandable Storage
The fastest certification (see: fast microSD cards) may be the A1 rating, but the best card for apps and media storage is the Samsung EVO+ (or the Select model from Amazon).
If partitioned into both internal and removable storage, you can sideload apps, ROMs, and flashable ZIP files, without needing to remove your card.
What’s your favorite microSD card? Any tips for getting more out of it? Let us know in the comments.
Image Credit: aleksanderdnp/Depositphotos