Xiaomi Redmi 9 is one of the most popular budget smartphones with support for memory expansion via microSD. But many users face problems: the phone does not see the card, data is not portable, or the speed of work leaves much to be desired. In this article, we will analyze all the nuances from choosing a card to fine-tuning the system for maximum performance.
We're not just going to tell you how to insert a card into a slot, but we're going to show you how to format it correctly (and why factory formatting over a phone often leads to errors), how to transfer apps and media files without losing data, and what to do if Redmi 9Suddenly stopped recognizing the drive. We're going to focus on the hidden MIUI settings that allow you to use the card as internal memory without losing speed.
Which memory card to choose for Xiaomi Redmi 9
Not all microSDs are equally useful. Redmi 9 supports cards up to 512GB, but there's a lot of confusion about speed class and format, and if you buy a cheap Class 4 or Class 6 card, it's going to slow down when you write files, and apps on the card might not run at all.
The best options for Redmi 9 are:
- 📌 Scope: 32 GB (minimum for media files) to 512 GB (for apps and games). 16 GB is too small, given the size of modern applications.
- ⚡ Class speed: UHS-I (U1 or U3) or A1/A2 (Optimized for Android. Maps. A2 Work faster with small files (ideal for applications).
- 🔄 Format: exFAT (for maps) >32 GB) or FAT32 (32GB). NTFS unsupported!
- 🛡️ Brand: SanDisk Ultra, Samsung EVO Plus, Kingston Canvas Go! – Proven and Uncounterfeited.
⚠️ Attention: Class Cards 10 marking U1/U3 or A1/A2 Often they are slower than stated. Before buying, check the reviews for a particular model - fakes for well-known brands are common.
How to insert a memory card in Xiaomi Redmi 9: Step-by-step
The memory card slot in Redmi 9 is paired with a SIM-slot tray, which means you can use either two nano-SIMs or one SIM+microSD. Keep that in mind when setting up!
Installation instructions:
- Turn off your phone (required! hot replacement can damage your contacts).
- Find a tray for SIM-cards on the left end of the phone (near the volume button).
- Insert the paperclip into the hole and carefully remove the tray.
- Put the nano-SIM in the first slot (if you need a connection), and the microSD in the second slot (with a microSD tag).
- Make sure the cards are placed with gold contacts down and do not protrude beyond the edges of the tray.
- Put the tray back in before the click.
When you turn on your phone, you'll see a notification of a new card. If you don't, check:
- 🔍 Is the card inserted correctly (turn the tray over and try again).
- 📵 Are the contacts contaminated (wipe with an alcohol napkin).
- 🔄 Does the phone support your card (see the section above on selection).
☑️ Check before installing the card
Formatting a memory card: FAT32, exFAT or internal memory?
After the first insertion of the card, Redmi 9 will suggest formatting it.
| Regime. | Advantages | Deficiencies | What's the point? |
|---|---|---|---|
| Portable storage (FAT32/exFAT) | ✅ Compatibility with PCs, cameras, other phones✅ Quick access to files | ❌ You can't install applications.❌ File size limit (4 GB for FAT32) | Music, photo, video, backup copies |
| Inner memory (Adoptable Storage) | ✅ You can install applications.✅ Encryption of data✅ A single space with built-in memory | ❌ The map cannot be retrieved without data loss.❌ Slower than internal memory❌ Not compatible with other devices | Applications, games, system files |
If you plan to use the card only for media files, choose Portable Storage with exFAT file system (it supports files over 4 GB).
⚠️ Note: When selecting the mode, the internal memory of Redmi 9 will format the card into EXT4 It will encrypt the data, and once the card is removed, it will not be read on another device, and it can slow down the phone if the card is not fast enough (below Class 10). U1).
What happens if you interrupt the formatting?
How to transfer data and applications to a memory card
You can do this in Redmi 9 in a number of ways, and let's look at each of them.
1. Transfer of media files (photos, videos, music)
The easiest way is to use the built-in File Manager:
- Open the Files app (folder icon).
- Go to Categories → Images / Audio / Video.
- Select files (long press) → More → Move.
- Choose. SD-destination-card.
To automatically save new photos/video to the map:
- Open the camera. → press on ⚙️ Settings.
- Choose Memory. → Memory map.
2. Transfer of applications to the map
If the card is formatted as internal memory, applications can be moved through the settings:
- Go to Settings → Applications → Application Management.
- Select the application → Warehouse.
- Click Change and select SD-map.
⚠️ Note: Not all apps support mapping. System applications (Google Play Services, MIUI Launcher and some games (e.g, PUBG Mobile can't be moved, and once it's moved, it can also run slower, which is normal for memory cards.
💡
Before transferring applications to the card, check its speed using the A1 SD Bench app (available on the Play Market). If the write speed is below 10 MB / s, it is better to leave the applications in the internal memory.
Problem Solving: Phone Cannot See Memory Card
If Redmi 9 doesn't recognize the map, there can be a variety of causes, from mechanical damage to software failures, and we'll look at the most common cases and how to fix them.
1.The map is not defined at all
Check it out.
- 🔌 Is the card inserted correctly (try turning over).
- 📱 Does the card work on another device (PC, other phone).
- 🔄 Are the contacts contaminated (clean with a swallow or alcohol).
- 🔧 Is the tray damaged for SIM-Check if the contacts are not bent).
If the card works on other devices but not on Redmi 9, try:
- 🔄 Reboot the phone.
- 📱 Update the firmware (Settings) → The phone. → Updating the system).
- 🔧 Reset network settings (Settings) → SIM-maps and mobile networks → Resetting network settings).
2.The map is defined but not formatted
If an error occurs when trying to format:
- 🖥️ Format the map on PC in FAT32 or exFAT (through Disk Management in Windows).
- 🔄 Try another card - the current one may be damaged.
- 🔧 Use the utility. SD Formatter from SD Association for Low Level Formatting.
3.The card is running slowly or "braking"
Reasons:
- 🐢 Low-class card (Class) 4/6).
- 🗑️ File fragmentation (especially if the card has been used for a long time).
- 🔋 Lack of energy (when connecting to a PC via a computer) USB).
Decisions:
- ⚡ Buy a class card A2 or U3.
- 🔄 Format the map (save the data before doing so!).
- 📵 Don't use cheap. USB-hubs when connecting to a PC.
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If the card starts to "glue" after the phone falls or moisture gets in, the contacts of the tray are most likely damaged, in which case only repairs at the service center will help.
Optimization of memory card on Xiaomi Redmi 9
To ensure that the memory card works quickly and does not slow down the system, follow these tips:
1. Caching setup
If the card is used as internal memory, turn on caching:
- Go to Settings. → Warehouse.
- Press on. SD-map → ⚙️ Settings.
- Enable Caching on the card (if the option is available).
Limitation of background activity
Memory card apps can slow down your phone, so to avoid:
- 🚫 Limit background activity for portable applications (Settings) → Annexes → Permits → Auto-start).
- 🔄 Regularly clean the cache of applications installed on the card.
3. Health monitoring of the card
Use the apps to check the status of the card:
- 📊 A1 SD Bench – Read/Write Speed Test.
- 🛡️ SD Card Tester – Checking for broken sectors.
- 📉 DiskInfo – wear monitoring (for cards) UHS-II).
If the recording speed fell below 5 MB / s, it is time to replace the card - it is worn out.
Security: How to protect data on a memory card
Memory cards are easy to lose or damage, so it is important to take care of data security:
1. Encryption
If the card is used as a portable storage, it can be encrypted:
- Go to Settings → Security → Encryption and credentials.
- Choose Encrypt. SD-map.
- Set your password (don’t forget it!).
⚠️ Warning: If you forget your password, the card data will be permanently lost, and encryption also reduces card speed by 10-15%.
2. Backup
Regularly copy important data from the map to the PC or cloud:
- ☁️ Use Google Photos to automatically upload photos/video.
- 💾 Connect your phone to your PC and copy files manually.
- 🔄 Use apps like Resilio Sync for automatic backup.
3. Protection against viruses
Memory cards are often a source of viruses, especially if you connect them to other devices.Install antivirus (such as Malwarebytes) and scan the card regularly:
- Open the antivirus.
- Select Scan. SD-map.
- Delete the threats you've detected.