How to format a memory card on Xiaomi Redmi Note 9 Pro: 4 proven methods

The memory card in the Xiaomi Redmi Note 9 Pro is not just an extra storage, but a way to expand the smartphone’s capabilities without unnecessary costs. However, over time, the microSD can start to slow down, emit errors or simply require cleaning before reuse. Formatting solves these problems, but wrong actions can turn the card into a “brick” or deprive you of important data.

This article presents 4 working formatting methods (including hidden MIUI features), file system parsing (FAT32 vs exFAT), and unique nuances for the Redmi Note 9 Pro that are not in the standard instructions, such as why a card can “disappear” from the system after a format via a phone and how to fix it without a computer.

Preparation: What to do before formatting

Before you click Format, make sure you don’t lose important data. Even if the card is empty, the system can store hidden files on it (such as app cache or.nomedia data).

Here is the checklist before starting:

Backup your data to your PC or cloud|Check the map for viruses (for example, through Malwarebytes)|Remove the card and inspect the contacts for damage|Make sure the battery is at least 50 times charged%|Disable the card as internal memory (if you use Adoptable Storage)-->

If you've previously configured your card as internal memory (via Settings → Memory → SD card), standard formatting via your phone won't work. You'll have to use an ADB or a computer, more on this in the alternatives section.

⚠️ Note: Redmi Note 9 Pro with firmware MIUI 12.5+ There's a bug: once the card is formatted as internal memory, the system can forget it after rebooting it. → Memory. → Map. SD → Settings (⚙️) → Portable format.

Method 1: Standard formatting through MIUI settings

The easiest way, which is suitable for most users, is for cards that are used as removable storage (not as internal memory).

Instructions:

1. Open the Settings → Memory.
2. Slip on the item SD Card (if it is not, check if the card is inserted correctly).
3. In the upper right corner, press on ⚙️ (Settings).
4. Choose Format → Format as internal or Format as portable (depending on your purpose).
5. Confirm the action. It'll take 1-3 minutes.

Important nuances:

• 🔹 Format as internal memory: The card will be encrypted and tied to the phone, and once it's extracted, it won't be readable.
• 🔹 Portable format: The card can be used on other devices, but some applications will not be able to write data to it.
• 🔹 File system: MIUI Automatically selects exFAT for cards >32 GB and FAT32 smaller.

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If the card is undetectable after formatting, try restarting the phone with the card extracted and then pasting it back in, which resets the MIUI cache responsible for recognizing the drives.

Method 2: Formatting with Recovery Mode (if the phone doesn’t boot)

If the Redmi Note 9 Pro is not turned on or is stuck in the boot cycle, but the memory card needs to be urgently cleaned, you can use the recovery mode, which is also useful if the MIUI gives an error "Map is damaged" and does not allow you to format it through settings.

Step-by-step:

1. Turn off the phone.
2. Press the Power button + Volume up until the Mi logo appears.
3. In the Recovery menu, select the language (volume buttons) and confirm Power.
4. Go to Advanced → Format SD card.
5. Confirm the action. Once completed, select Reboot.

Warnings:

• 🚨 This method does not work if the card is used as an internal memory (Adoptable Storage).
• 🚨 On some custom firmware, Format item SD card may not be available.

⚠️ Note: In Recovery Mode, Redmi Note 9 Pro formats the map into FAT32, Even if it's over 32 GB, that's a firmware restriction. If you want exFAT, use 3 or 4.

Method 3: Computer Formatting (for cards >64 GB)

If you need an exFAT file system (for example, to write files >4 GB), and MIUI persistently formats the card in FAT32, the computer will help. This method is also useful if the phone does not see the card due to file system errors.

Instructions for Windows:

1. Connect the card to the PC through the card reader.
2. Open This computer, find a removable disk (map), right-click → Format.
3. Select the file system: FAT32 for compatibility with all devices (max. file 4 GB), exFAT for files >4 GB (eg, 4K video). NTFS is not recommended for Android (may not be readable).

Click Start and wait until it is completed.

For macOS/Linux, use:

• 🍎 Mac: Disk utility → Erase → Format: exFAT.
• 🐧 Linux: sudo mkfs.exfat /dev/sdX1 (substitute sdX1 On your drive, find it through lsblk).

Method 4: Alternative formatting via ADB (for power users)

If the memory card is used as an internal memory card, but you want to return it to its original state, standard methods will not work. ADB — Android debugging tool.

Instructions:

1. Install ADB Tools on your PC.
2. Turn on the phone Debugging over USB (Settings → About Phone → MIUI Version (tap 7 times) → Additional → For developers → Debugging over USB).
3. Connect your phone to your PC and execute commands: adb shell sm list-volumes Find a line with private or mixed in the output - this is your card.
4. Format the map with the command: sm partition disk:179.64 private (replace 179.64 with your values from the output sm list-volumes).
5. Reboot your phone: adb reboot

⚠️ Note: Incorrect commands in the ADB This can cause you to lose all the data on your phone, not just your card. If you're not sure, use method 3 (via your computer).

Common mistakes and their solutions

Even after successful formatting, the memory card may not behave properly.-5 problems and ways to correct them:

• 🔴 «Map corrupted": Cause: Incorrect extraction or failure of the file system.Solution: Format the card via a computer (method 3) with the choice of exFAT.
• 🔴 «Card undetectable": Reason: Card or slot contacts are contaminated.Solution: Wipe the card contacts with alcohol, check the slot for debris.
• 🔴 «Not enough space" when recording: Reason: Map formatted in FAT32, And you're trying to write a file. >4GB Solution: Reformat to exFAT (method 3).
• 🔴 «The map became "raw» (RAW): Reason: Critical File System Error Solution: Use DiskPart utility in Windows: Diskpart list disk select disk X (where X is your card number) clean create partition primary format fs=exfat quick

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If the memory card after formatting is slow, check it for authenticity using the utility h2testw – many “brand” cards on the market are fakes with low speed.

How to check a memory card after formatting

To make sure the card is working correctly, do 3 tests:

1. Speed Test: Use the App A1 SD Bench (available from Play Market) Normal values for Redmi Note 9 Pro: 📊 Reading: >80 MB/s (for UHS-I). 📊 Recording: >20 MB/s (for Class 10).

If the speed is lower, the card is worn out or fake.

Error Test: Copy a large file (like a movie) onto a map, then compare its hash amount (via Hash Droid) to the original. If the hashes don't match, the card is corrupted.

Capacity test: Fill the card with "tipped" files, and if the actual volume is less than the declared volume, it is a fake.

If the tests fail:

• 🛑 For new cards: return to the seller (guarantee case).
• 🛑 For older maps: Try low-level formatting through HDD Low Level Format Tool (for power users only!).

FAQ: Frequent questions about Xiaomi memory card formatting