Owners of smartphones on Android 9 Pie often face a lack of built-in memory, especially if the device is budget or was released several years ago. One solution is to use microSD card as internal storage, which allows you to install applications, games and save data directly to a removable drive. However, Android 9 this process has features that are important to consider before setting up.

Unlike newer versions of the OS (for example, Android 10+where the adapted storage function works differently), c Pie formatting the card as internal memory leads to its encryption and binding to a specific device. This means that once configured, the card cannot simply be removed and read on another gadget or PC - it will become part of the system. In this article, we will look at how to correctly perform the procedure, what restrictions exist and how to avoid common mistakes.

What is “internal memory” on an SD card and why do you need it

When you format microSD as internal storage, Android creates an encrypted partition on it, which the system perceives as part of the main memory. This allows you to:

  • 📱 Install applications and games directly to the card (including updates).
  • 📁 Save application data (cache, settings, downloads) to SD.
  • 🔄 Free up built-in memory for system files and temporary data.

However, there is a downside: after formatting the card becomes incompatible with other devices. For example, if you remove it and insert it into another smartphone or computer, the data will not be available without additional manipulations. In addition, performance applications on the SD card may be lower than in the built-in memory, especially if you use a cheap drive class Class 4 or Class 6.

📊 Which microSD class are you do you use?
Class 10 (UHS-I)
Class 10 (regular)
Class 6 or lower
I don’t know
Other

It is important to understand that not all applications support installation on SD. For example, some games (for example PUBG Mobile or Genshin Impact) may refuse to work from external storage due to read/write speed requirements. It is also worth considering that Android 9 Pie does not support the function Adoptable Storage on all devices - some manufacturers (for example, Samsung or Huawei) block it in their shells.

Requirements for an SD card for use as an internal memory

Not every microSD is suitable for formatting as internal storage. Here are the key requirements:

  • 🔹 Minimum volume: 8 GB (recommended 32 GB and above).
  • 🔹 Speed class: not lower Class 10 or UHS-I (U1/U3). Cards Class 4/6 will slow down the system.
  • 🔹 File system: after formatting, Android converts it to ext4 or f2fs (depending on the device).
  • 🔹 Compatibility: the card must be supported by your smartphone (check the maximum capacity in the specifications).

If you use a low-end card (for example Class 4), the system may display errors when installing applications or operating them. For example, games with high reading speed requirements (for example Call of Duty Mobile) will slow down or crash. You should also avoid fake cards - they often have a real volume less than declared and quickly fail.

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Before purchasing, check the card for authenticity using the utility H2testw (Windows) or F3 (Linux/macOS). This will help you avoid buying fake drives.

Characteristics Minimum requirement Recommended value
Volume 8 GB 32–128 GB
Speed class Class 10 UHS-I (U3)
File system before formatting FAT32/exFAT exFAT (for cards >32 GB)
Service life — Cards with a 5+ year warranty (for example, SanDisk Ultra)

Please note: after formatting the card as internal memory, it cannot be used to store regular files (photos, videos, music) in the usual form. All data will be encrypted and can only be accessed through the Android file system. If you need both, consider the option with by dividing the card into two parts (one as internal memory, the other as portable storage), but this requires root access.

Step-by-step guide: how to make an SD card internal memory on Android 9

Before starting the procedure required make a backup copy of the data from the card - all files will be deleted. Also make sure that the battery is charged at least 50% to avoid failures.

Save important data from the card to your PC|Charge your smartphone to at least 50%|Check the speed class of the card (Class 10/UHS-I)|Make sure the card is compatible with the device (max. capacity)|Disable antivirus (may block process)

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Now let's move on to the setup:

  1. Insert microSD into the smartphone. If the card is new, Android will prompt you to format it - select Configure as internal storage (or a similar item, if the card has already been used, go to Settings → Storage.

  2. Tap on the name of the SD card (for example, SD card: 64 GB) and select Settings (the ⚙️ icon in the upper right corner).

  3. In the menu, select Format as internal storage. The system will warn that all data will be erased - confirm the action.

  4. Wait for the process to complete (it may take 5-15 minutes depending on the size of the card). After this, the smartphone will offer to transfer the data - select Move now or Postpone.

  5. Reboot the device for the changes to take effect.

After rebooting, check that the card is displayed as part of the internal memory. To do this, go to Settings → Storage - you should see the combined volume (for example, Internal memory: 32 GB + 64 GB).

What to do if there is no "Format as internal storage" item?

On some devices (for example, smartphones Samsung with shell One UI or Xiaomi c MIUI) the manufacturer can block this function. In this case, there are two options:

  1. Use ADB commands (you need to enable USB debugging and connect the smartphone to PC).
  2. Install custom firmware (for example, LineageOS), if it supports Adoptable Storage.

For more information about the ADB method, read the following section.

Formatting an SD card as internal memory via ADB (if the standard method does not work)

If the settings of your smartphone do not have the option to format SD as internal memory, you can use ADB (Android Debug Bridge)This method works on most devices with Android 9 Pie, but requires connection to. computer.

You will need:

  • 🖥️ Computer with installed drivers ADB (you can download from the website Android Developers).
  • 📱 USB cable (preferably original).
  • 🔧 Enabled USB debugging on the smartphone (path: Settings → About phone → Number assembly (tap 7 times) → Settings → System → For developers → USB debugging).

Instructions:

  1. Connect your smartphone to the PC and open Command Line (Windows) or Terminal (macOS/Linux).

  2. Enter the command to check the connection: 

    adb devices

    If the device is displayed in the list, proceed further.

  3. Run the command to format the SD card (replace disk:179,XX with the current ID of your card, which can be found with the command adb shell sm list-disks): 

    adb shell sm partition disk:179,XX private

  4. Wait for the process to complete and reboot your smartphone.

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Usage ADB is the only way to enable Adoptable Storage on smartphones with custom skins, where the function is hidden by the manufacturer. However, this method requires caution: an incorrect command can lead to data loss or system failure.

If after executing the commands the card does not appear as internal memory, check:

  • ✅ The entered disk identifier is correct. (disk:179,XX).
  • ✅ Superuser rights (if required) root).
  • ✅ Card compatibility (some devices do not support cards larger than 128 GB).

How to transfer apps to SD card after setup

After microSD has become internal memory, you can transfer applications to it. However, not all apps support this feature. Here's how to do it:

  1. Open Settings → Applications and notifications → All applications.

  2. Select the application you want to transfer (for example, Facebook or Spotify).

  3. Tap on the item Storage (or Memory).

  4. If the option is available, you will see a button Change or Move to SD card. Press it and wait for the process to complete.

Please note:

  • 🚫 Not all applications can transfer. For example, system utilities or apps with high performance requirements (for example, Google Maps or Netflix) often block this function.
  • ⚠️ Transferring applications to SD can lead to them if the card is not enough. fast. slow operation, if the card is not fast enough.
  • 🔄 After transfer, some data (cache, temporary files) may remain in the built-in memory.
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To free up maximum space, transfer rarely used applications or heavy games first (for example, Asphalt 9 or Call of Duty).

If the button Move to SD card is inactive, this means that the developer has prohibited moving his application. In this case, you can try:

  • 🔧 Use applications like App2SD (requires root).
  • 📁 Manually transfer part of the data (for example, downloads or media files) through a file manager.

Limitations and problems when using an SD card as internal memory

Despite the obvious advantages, this method has several serious disadvantages:

⚠️ Attention: After formatting the card as internal memory, it cannot be used on other devices without completely erasing the data. Also, some applications (for example, WhatsApp or Telegram) may refuse to work from external storage due to security policies.

Main problems:

  • 🐢 Reduced performance: even class cards UHS-I (U3) are slower than the built-in memory eMMC/UFSThis is especially noticeable in games and heavy applications.
  • 🔒 Data encryption: the card is tied to the device, and if it is removed without proper unmounting, data loss is possible.
  • 🚨 Risk of data loss: if the card fails, it will be extremely difficult to recover information (unlike regular FAT32/exFAT).
  • 📵 Incompatibility with some applications: banking apps (for example, SberBank Online) or instant messengers can block work with SD for security reasons.

It is also worth considering which Android 9 Pie does not support dynamic memory allocation between the built-in storage and the SD card. This means that if the internal memory is full, the system will not be able to automatically use the free space on the card - you will have to manually transfer the data.

Problem Cause Solution
Applications crash after transferring to SD Low card read/write speed Use card class UHS-I (U3) or transfer the application back
The card is not detected after reboot Incorrect extraction or file system failure Reformat the card or check for errors via PC
Cannot transfer some applications Developer restrictions or system applications Use root or leave in the built-in memory

If you decide to return the card to its original state (for example, for use on another device), you will have to completely format it via a PC or smartphone. this:

  1. Go to Settings → Storage → SD card.
  2. Select Format as portable storage (or Clear).
  3. Confirm the action - all data will be erased.

Alternative ways to expand memory on Android 9

If using an SD card as internal memory seems too risky or inconvenient, consider alternative options:

  • 📁 Moving media files: Photos, videos and music can be manually moved to an SD card (formatted as portable storage) via the file manager.
  • ☁️ Cloud storage: Google Drive, Yandex Disk or Dropbox allow you to free up space by transferring files to the cloud.
  • 🔄 Clearing the cache: regularly clearing temporary files (for example, via Settings → Storage → Clear cache) can free up several gigabytes.
  • 📱 Using OTG drives: flash drives with a connector USB-C or Micro-USB (if supported OTG).

To automate the transfer of files, you can use applications like Files by Google or SD Maid. They analyze the memory and offer to delete unnecessary data (duplicates, old downloads, cache).

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If your smartphone supports USB OTG, an external SSD drive (for example, SanDisk Extreme Portable) can be an excellent alternative to an SD card - it is faster and more reliable, especially for working with large files.

If the problem is lack of space for applications, and transferring to SD is impossible, consider:

  • 🗑️ Removing unnecessary apps (via Settings → Applications).
  • 🔄 Using Lite versions applications (for example, Facebook Lite or Messenger Lite).
  • 📦 Disabling pre-installed applications (bloatware) if they are not used.

FAQ: Frequently asked questions about using an SD card as internal memory

Can I use SD card as internal memory on all smartphones with Android 9?

No, some manufacturers (for example, Samsung, Huawei, Xiaomiblock this function in their shells. In this case, only ADB or custom firmware will help.

What happens if you remove the SD card? formatted as internal memory?

The smartphone may become unstable, and some applications may crash. When you reinsert the card, the data will remain, but if you format it on another device, all files will be lost.

Can I transfer WhatsApp or Telegram to an SD card?

Officially, these messengers do not support transferring to external storage for security reasons. However, you can manually move media files (photos, videos) through the chat settings.

How to return the SD card to normal mode after using it as internal memory?

You need to format it via Settings → Storage → SD card → Format as portable storage. All data will be deleted.

Why do applications on the SD card run slower?

The read/write speed of even the fastest microSD (class UHS-I U3) is lower than that of the built-in memory (eMMC 5.1 or UFS 2.1) This is especially noticeable in games and applications that actively work with the cache.