Why is it that combining memory on Xiaomi is not always a good idea?
Xiaomi smartphone owners (especially the budget Redmi and POCO series) often face a shortage of internal memory. The solution seems obvious: buy a microSD card, insert it into a slot and “merge” everything into a single storage. But Adoptable Storage technology (the adopted Android standard for combining memory) works on Xiaomi devices with a number of limitations. Even if your model supports this feature, the consequences can be unexpected.
The fact is that MIUI (Xiaomi firmware) modifies the standard Android mechanism, for example, once combined, the card is encrypted and cannot be read on another device without being reset, and some models (such as the POCO X3 Pro or Redmi Note 10) automatically format the card into the F2FS file system, which can lead to data loss when extracted. Before you act, see if your smartphone is suitable for such an operation.
This article provides a step-by-step guide to MIUI 14/15 features, a list of supported models, alternative ways to expand memory and answers to frequent questions, and critical warnings that the manufacturer does not mention.
Which Xiaomi models support memory integration?
Adoptable Storage is not available on all Xiaomi devices, but here are the key terms:
- 📱 Android version: not lower than Android 6.0 Marshmallow (but in practice it works stably with Android 9)+).
- 🔧 Firmware: official MIUI Global or MIUI Castomic firmware (e.g. Pixel Experience) can block the function.
- 💾 Type of slot: only hybrid slots (where the second slot is located) SIM Devices with a separate card slot (e.g. Redmi Note 12 Pro)+) They don't support the union.
Below is the compatibility table of popular models (the data is relevant for MIUI 15):
| Model | Adoptable Storage Support | Features |
|---|---|---|
| Redmi Note 10/11/12 | ✅ Yes. | It requires formatting in F2FS. Once combined, the card becomes “internal” forever. |
| POCO X3/X3 Pro | ✅ Yes (with limitations) | MIUI 13+ may have mounting errors, and Class A2 cards are recommended. |
| Mi 11/12/13 | ❌ No. | A separate microSD slot. The unification is locked at the firmware level. |
| Redmi 9/9A/9C | ✅ Yes. | Supports only cards up to 512 GB. If the limit is exceeded, the error "Not enough space for metadata" is used. |
| POCO F3/F4/F5 | ⚠️ Partially. | The feature is available, but after upgrading to MIUI 15, there are possible lags when writing files to a card. |
If your model is not listed, check support through the Settings menu. → Memory. → [Name of the map] → Three points (⋮) → If you don't have "Use as internal memory" option, the function is blocked.
⚠️ Attention: On devices with MIUI For example, the Redmi Note 11 Pro+ 5G) This feature may be hidden due to local constraints. Try changing region to India or Global in the settings.
Preparation SD-maps: what class and volume to choose?
Not every microSD is suitable for combining with internal memory.
- 🔢 Speed class: minimum UHS-I (U1), better A2 (For example, SanDisk Extreme A2 Samsung EVO Class cards C10 marking A1/A2 brake.
- 💾 Volume: from 32 GB to 1 TB. Optimal - 128-256 GB (more is not always better: MIUI It may not be able to handle cards correctly. >512GB).
- 🔄 File system: the card will be formatted into ext4 or F2FS (All the data on it will be erased!
Before buying, check the card for authenticity with the help of the utility H2testw (Windows or F3 (Linux/macOS). Counterfeiting (especially cheap «512 GB for 1000 RUB often has a real volume in 10–20 less than the stated.
Buy an A2 class card (e.g. SanDisk Extreme)
Make a backup copy of data from the card
Charge your phone at least 50%
Connect to stable Wi-Fi (required to check the card)
Disable two-factor authentication in MI-account (during the procedure)-->
If you use a card from an old phone, be sure to:
- Copy all the files on the PC.
- Format it in FAT32 via your phone (not PC!).
- Check for errors in the Settings menu → Memory → [Map] → Format.
⚠️ Warning: Once combined, the map becomes an integral part of the system, if you remove it, the applications installed on it will stop working, and the phone may freeze when it boots.
Step-by-step instructions: how to combine SD-memory-card
If you're confident in your model and your map, follow the instructions. It's irreversible! Once combined, you can only return the card to its original state through a complete reset of the phone.
- Insert the card into the slot (when the phone is turned off, if the slot is hybrid).
- Turn on the phone and wait for the card to be identified.
- Go to Settings → Memory (or Storage).
- Tap your name on it. SD-maps (e.g. SanDisk) 128GB).
- In the upper right corner, press three dots (⋮) → Storage settings.
- Choose Use as internal memory (or Format as Internal in English firmware).
- Confirm the formatting. The phone will reboot.
- After the reboot, wait until the application optimization process is complete (it can take up to 10 minutes).
If the item is not used as internal memory:
- 🔹 Try to update. MIUI last-minute.
- 🔹 Change the region in settings to India (Settings) → Additionally. → Region).
- 🔹 Use it. ADB-team (instruction below).
After a successful merger:
- 📁 The map will be displayed as part of the internal memory in the Warehouse menu.
- 🔄 Applications can be transferred manually (Settings) → Annexes → [Annex] → Memory. → Change).
- ⚠️ The card’s speed will be lower than that of the internal memory (especially noticeable in games and heavy applications).
What to do if the phone freezes after the merger?
ADB Connection: If the Standard Method Does Not Work
On some models (such as the POCO F3 or Redmi K40), the unification point is hidden, but the function can be activated via Android Debug Bridge (ADB).
- 🖥️ Computer with drivers installed ADB.
- 🔌 USB-cable (preferably original).
- 📱 Included debugging by USB (Settings → The phone. → Version. MIUI → 7 times to tap according to the version → return to → For developers → Debugging by USB).
Instructions:
- Connect the phone to the PC and confirm the debugging on the screen.
- Open the command prompt (Windows) or terminal (macOS/Linux) in the folder with ADB.
- Enter the command to check the connection: Adb devices must appear serial number of your device.
- Execute the command to combine (replace X with your card number, which can be recognized by the adb shell sm list-disks command): adb shell sm set-force-adoptable true adb shell sm partition disk:X private
- Reboot the phone.
If the team fails, try an alternative method:
adb shell sm set-force-adoptable true
adb shell sm partition disk:X mixed 25Where 25 is the percentage of memory reserved for cache (can be changed by 10–50).
⚠️ Attention: Misuse of the right ADB If you're not sure, don't experiment. Better use the card as a portable storage device (without combining).
💡
Before using ADB, back up your Settings → Additional → Backup. This will save your contacts, SMS, and application settings, but not your files on the map!
What will happen after the merger: pros and cons
Memory integration solves the problem of space scarcity, but it has serious drawbacks.
| Pluses | Cons |
|---|---|
| ✅ Increased Available Memory for Applications. | ❌ The map becomes tethered to the phone, and on another device, you can't read it without formatting it. |
| ✅ You can port games and heavy apps (such as Genshin Impact or Call of Duty Mobile). | ❌ Read/write speed is lower than that of built-in memory (lags in games, slow loading of levels). |
| ✅ You don't have to keep cleaning the cache. | ❌ When you remove the map, the applications installed on it will stop working. |
| ✅ Cheaper than buying a phone with more internal memory. | ❌ Risk of data loss in case of card failure (SD less reliable than internal memory UFS). |
The most critical downside is the card dependency, which means that if it fails (and microSDs have a limited record life), you lose all the data, including the apps you installed, and you can't recover it without a backup.
The alternative is to use the card as a portable storage device (without combining) and manually transfer files (photos, videos, music) to it, which is safer, but does not solve the problem of installing applications.
💡
Memory combination is only suitable for budget models with a hybrid slot and A2 class cards. For flagships (Mi 13, POCO F5 Pro) it is better to buy a version with 256 GB of internal memory.
Alternatives to Unification: How to Expand Memory Without Risks
If you are afraid of the disadvantages of Adoptable Storage, consider these methods:
- 🔄 Manual File Transfer: C Settings → Memory. → Select the internal memory of large files (video, APK) and transfer them to SD-card (as a portable storage device).
- ☁️ Cloud services: Mi Cloud (5 GB free), Google Drive (15 GB) or Yandex Disk. Automatically upload photos/video through the Gallery → Settings → Autoboot.
- 📱 USB-OTG drive: connect the flash drive through the adapter. MIUI It will be defined as a removable disk (you can store movies, music).
- 🗑️ Cache Cleanup: Use the built-in Cleanup utility (Settings) → Memory. → Clean) or the Files by Google app.
- 🛠️ Root + App2SD: Once you have root rights, you can link the application folders to the SD-via FolderMount or Link2SD.
For games, the best solution is a class A2 microSD card + transfer through Settings → Apps → [Game] → Memory → Change. For example, Genshin Impact (15+ GB) or Honkai: Star Rail (10+ GB) can be transferred without combining memory.
If you often shoot 4K or 8K video, consider buying an external SSD (like the Samsung T7 Shield) and plug it in via USB-C. The speed of recording will be faster than that of a microSD, and the reliability will be like that of a hard drive.