Owners of Xiaomi Redmi 9 often face a lack of internal memory, especially if the device is used for games, photos or videos. SD-The map seems to be a logical solution, but in MIUI This feature doesn't work as clearly as other Android environments, and the problem is compounded by the fact that the manufacturer limits the ability to format the drive as internal storage (Adoptable Storage) on budget models.
In this article, we will discuss all working methods of transferring data to SD-map 9 (including versions of Redmi 9A/9C/9T), particularity MIUI 12–14. You will learn how to get around the limitations of the system, which applications can be moved and which can not, and what to do if the phone does not see the memory card after formatting.
Why Redmi 9 doesn’t allow you to move apps to the next SD-map?
The main reason is the security and performance policies of Xiaomi and Google, and since Android 6.0, Google has introduced the Adoptable Storage concept. SD-It's a card as part of the internal memory:
- 🔹 Xiaomi blocks this feature on budget models (including Redmi) 9) Due to the low speed of microSD (class) A1/A2 It does not guarantee stability).
- 🔹 Some apps (e.g. WhatsApp, Banking) prohibit transfers for security reasons.
- 🔹 MIUI hides the option of formatting the map as internal storage in some regional firmware.
Also, even if you manage to format a card as internal memory, not all application data will be transferred, such as cache and updates often remain in internal memory, which is due to the Android architecture, where some application files (/data/app-lib) are tightly tied to the main storage.
Preparation SD-maps: what class and volume to choose?
For Redmi 9, it is critical to choose the right memory card, and the performance of the system when using SD as internal storage depends on the speed class:
| Class of card | Minimum speed | Is it suitable for Adoptable Storage? | Models of example |
|---|---|---|---|
| Class 10 (U1) | 10 MB/s | ❌ No (brake) | SanDisk Ultra, Kingston Canvas Select |
| A1 | 10 MB/s (1500 IOPS) | ⚠️ Partially (lags in multitasking) | Samsung EVO Plus, Lexar 633x |
| A2 | 10 MB/s (4000 IOPS) | ✅ Yes (optimally) | SanDisk Extreme, Kingston Canvas Go! Plus |
A 64-128 GB A2 card is recommended for porting applications. 256 GB+ cards often run slower due to the controller's features. Avoid cheap no-name cards, which can fake a speed class, leading to permanent lags or even data loss.
⚠️ Note: If you are planning to use SD-The card is like internal memory, and all the data on it will be deleted when formatted.
Method 1: Formatting SD-The card as an internal storage (Adoptable Storage)
This method allows you to expand your internal memory. SD-maps, but not on all firmware MIUI. The instructions are relevant for Redmi 9S MIUI 12–14 (including European and global versions):
Make a backup copy of data from the card|Charge your phone at least 50 times%|Use a class card A2|Disable two-factor authentication in Mi Account (during the procedure)-->
- Put it in. SD-Redmi 9 slot card (up to 512 GB cards supported).
- Go to Settings → Memory (or Storage).
- Tap by name. SD-map → Settings (three dots in the upper right corner) → Storage settings.
- Select Internal Memory (if you don’t have an option, see the Hidden Settings section).
- Confirm the formatting. It takes 5-15 minutes, depending on the size of the map.
After formatting:
- 📱 The phone will offer to transfer data from internal memory to SD-Agree, it will speed up the process.
- 🔄 Some apps (like Google Play Services) won’t migrate – that’s OK.
- ⚡ System speed can decrease by 10-30% (depending on the class of the card).
⚠️ Note: After formatting SD-It's not going to be read on other devices without being completely erased, and it's going to be encrypted, and when you reset your phone to the factory settings, it's going to be inaccessible.
What if the option “Inner Memory” is not available?
Method 2: Manually porting applications (without formatting) SD-map)
If you don't want to format the card as internal memory, you can only transfer some of the apps through standard Android settings.
- Open Settings → Applications → Application Management.
- Select the app you want to migrate (like Facebook or Spotify).
- Tap the Warehouse → Change (if the button is inactive – transfer is impossible).
- Choose. SD-map and confirm the action.
Limitations of the method:
- 🚫 Most system applications and games (e.g, PUBG Mobile, Call of Duty do not support portability.
- 📁 Only parts of the data are transferred (main files remain in internal memory).
- ⚠️ After the transfer, some applications may not work stable (for example, Telegram notifications).
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To find out which apps to port, use the free AppMgr III app (available on Google Play), which shows a list of compatible programs and estimates the memory gain after transfer.
Method 3: Use Link2SD (for rooted devices)
If your Redmi 9 has root rights, you can use Link2SD to force data transfer, a method that circumvents MIUI restrictions, but requires caution:
- Install Link2SD from Google Play.
- When you first start, select the FAT32 or ext4 file system (the latter is preferred).
- Reboot the phone.
- In the list of applications, select the desired → Create a link → tick Application Data and Cash.
The advantages of Link2SD are:
- ✅ Transfers all application data (including cache and updates).
- ✅ Works with applications that don’t normally support portability.
- ✅ Allows you to automatically transfer new applications.
⚠️ Attention: Misuse of the right Link2SD This can cause data loss or a cyclical restart of the phone. TWRP Mi Cloud.
Addressing common mistakes
When transferring data to SD-Redmi 9 users often face problems:
| Mistake. | Reason. | Decision |
|---|---|---|
| The "Transfer" button is inactive. | The application does not support portability or the card is formatted as portable | Use Link2SD (root required) or format the card as an internal one |
| The phone can't see. SD-map | Incompatible file system or encryption error | Reformat the card to FAT32 via PC and repeat the procedure |
| Apps fly out after transfer | Low speed of reading/writing cards (class below A2) | Return apps to internal memory or buy an A2 class card |
| There's not enough room for SD-map | MIUI reserves 10-15% of the space for system needs | Use a larger card or clear the cache through Settings → Memory |
If after transferring applications the phone began to slow down, try:
- 🔄 Disable animation in Settings → The phone. → Version. MIUI (tap 7 times, then install animation in the developer settings = 0.5x).
- 🧹 Clear the cache through SD Maid or built-in cleaning utility.
- 🔋 Restart your phone in Safe Mode (hold the power button) → Restarting in Safe Mode).
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If, after formatting, SD-The phone stopped turning on, retrieve the card and re-start. Often this is due to an encryption error. + Vol Down when switched on).
Alternative ways to free up memory
If the applications are transferred SD-The card didn’t solve the memory problem, consider these methods:
- 🗑️ Cache cleaning: In Settings → Memory. → You can delete up to 1-3 GB of unnecessary files. Use Files by Google for deep cleaning.
- ☁️ Cloud Storage: Move photos and videos to Google Photos (up to 15GB free) or Mi Cloud (up to 5GB for Xiaomi accounts).
- 🎮 Lite versions of apps: Install lightweight versions of software (e.g. Facebook Lite, Messenger Lite) that take up 2-5 times less space.
- 🔧 Disabling Pre-installed Applications: Through Settings → Apps can be disabled by unnecessary Xiaomi services (e.g. Mi Video, Mi Music).
For games, we recommend using an external hard drive through OTG-Adapter: For example, Redmi 9 supports up to 2TB of storage (exFAT format) to store heavy games (Genshin Impact, Call of Duty) without loading on internal memory.