Xiaomi Redmi 9 smartphone owners often face a lack of internal storage, especially when installing a large number of applications and games with high-resolution graphics. built-in memory of 64 or 128 GB may not be enough to store thousands of photos, videos in the video. 4K And the solution to this problem is to use external media. USB-storage device connected via port USB Type-C. However, before starting work, the device must be properly prepared so that the Android system can correctly read and write data.
The formatting process on MIUI devices has its own peculiarities, different from the storage process on a personal computer. The operating system requires a certain file structure to work with external data sources in a stable manner. If you ignore this step, the phone may simply not see the flash drive or give an error when trying to copy files. It is important to understand that formatting will completely destroy all data, so you need to approach the procedure consciously.
In this article, we will discuss in detail all the stages of preparing the drive, choosing the optimal file system and how to circumvent restrictions if standard methods of formatting the flash drive fail. You will learn how to turn your Xiaomi Redmi 9 into a powerful multimedia center with advanced storage.
Preparation of equipment and compatibility check
The first step before you start any data manipulation is to physically check the hardware. Your Xiaomi Redmi 9 is equipped with a USB 2.0 Type-C port that supports OTG (On-The-Go) technology. This means that the smartphone can work as a host and supply power to connected devices. However, not all flash drives can work directly due to differences in connector shape or power consumption.
If you use a standard USB Type-A flash drive, you will need a special adapter or OTG cable adapter. The quality of the adapter plays a critical role: cheap accessories may not provide stable contact or enough voltage, which will lead to permanent shutdowns of the drive while running.
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Use original or certified OTG cables, as cheap counterparts often don’t have a resistor signaling the phone to connect an external device.
Also consider power consumption. If you connect a volumetric external hard drive, the Redmi 9 battery may not be enough to spin it. USB-It's not usually a problem for a conventional flash drive, but heating the phone in the area of the connector during active recording is a normal physical process.
- 🔌 Check for an adapter. USB Type-C to USB Type-A complete or buy a quality analogue.
- 🔋 Make sure that the smartphone charge is at least 20-30% pre-recording.
- 💾 Backup important data if there is already information on the drive that cannot be lost.
- 📱 Check the phone’s charging port for dust and pile, which can interfere with tight contact.
Connecting the drive and primary diagnosis
Once you've prepared everything you need, plug the flash drive into your smartphone. MIUI, installed on Xiaomi Redmi 9, usually instantly responds to the connection of external storage. at the top of the screen, in the notification area, the corresponding icon should appear. USB-If you pull the notification curtain down, you'll see a message saying that USB-the device is connected and prompt to open it to view files.
In some cases, the system may not open the file manager automatically, but the notification will remain. Click on it to go to the memory management section. If there are no reactions, try reconnecting the device or rebooting the smartphone. Sometimes Android drivers may fail, and simply restarting the Media Storage service or the entire phone solves the visibility problem.
When a drive is defined, but when you try to write a file, there is an error, this is a sure sign of file system incompatibility. Android works perfectly with the FAT32 format, but has a limit on the size of one file at 4 GB. More modern formats, such as exFAT or NTFS, may require special support or formatting using the phone, not the computer.
⚠️ Note: If the phone emits a connection audible when connecting a flash drive, but the device does not appear in the list, the file table or connector may be damaged.
For initial diagnosis, you can go to the storage settings. The path usually looks like: Settings → About Phone → Memory or through the Explorer app. Here you will see the total and free capacity of the connected device. If the volume is displayed correctly, but the recording is impossible, then it is time for formatting.
Formatting the MIUI system
The safest and most recommended way to prepare a flash drive to work with Xiaomi Redmi 9 is to use the built-in operating system tools, which ensures that the optimal file system and partition structure is chosen, understandable by the current version of Android. To start, open the Explorer app or go to Settings. → Memory.
Find your flash drive in the list of connected devices (it can be called) USB-Click on it to open the control menu. In the window that opens, select Settings (often indicated by three dots or a gear) and select the option "Format" or "Clear" from the action menu. USB-accumulator».
☑️ Algorithm of formatting in MIUI
The system will issue a warning that all data will be deleted. Confirm the action. The process takes from a few seconds to a couple of minutes depending on the storage capacity. During this procedure, do not remove the flash drive or turn off the phone screen so as not to damage the recording sectors. Once completed, the phone will suggest using the drive as a portable storage.
The advantage of this method is that MIUI chooses the right format for itself. For drives up to 32 GB, this is likely to be FAT32. For 64 GB and higher, the system more often chooses exFAT, which is free of file size restrictions and supports large amounts of data, which makes the flash drive versatile for storing high-quality movies.
File system selection: FAT32, exFAT or NTFS
Understanding the differences between file systems is critical to making efficient use of external storage on the Xiaomi Redmi 9. Each has its own advantages and disadvantages, which affect compatibility with other devices and maximum file size.
FAT32 is the oldest and most compatible format, and it reads on almost any device, from old radios in cars to game consoles and TVs. But it has a serious limitation: it doesn't support files larger than 4GB. If you plan to store high-resolution movies or disc images on a flash drive, it won't work for you.
exFAT is a modern replacement for FAT32, designed specifically for flash memory. It removes the 4GB limit and supports huge amounts of data. Xiaomi Redmi 9 works with this format without problems. It is the ideal choice if you use the flash drive only with modern gadgets and computers running Windows or macOS.
NTFS is the native Windows file system. It supports logging, which increases reliability, but on Android it requires special support. Often phones can only read NTFS data, but not write it without root rights or special drivers, so it is less preferable for use with a phone.
| File system | Max. File size. | Compatibility | Recommendation |
|---|---|---|---|
| FAT32 | 4GB | Maximum (TV, Auto, PC) | For music and documents |
| exFAT | 16 EB (theor) | High (Smartphones, PCs) | For 4K video and large archives |
| NTFS | 16 EB (theor) | Windows (limited to Android) | Just for reading on the phone. |
Why can’t your phone see files larger than 4GB?
Use of third-party applications for formatting
There are times when the standard Xiaomi Redmi 9 tools fail to format the flash drive, which may be due to a damaged partition table, the presence of hidden partitions, or a specific format that the phone cannot process on its own, in which specialized applications from Google Play come to the rescue.
One of the most powerful tools is the DriveDroid app (requires root) or simpler utilities like USB OTG Helper and File Commander, these programs have their own drivers and can force you to initiate the formatting process to the desired file system. USB-device.
⚠️ Warning: When using third-party software, carefully monitor the choice of disk. A one-click error can lead to formatting the phone's internal memory instead of a flash drive.
In the program interface, select the connected USB-It's usually displayed as a separate device with a letter or a name. Select Format or Wipe. You'll be asked to choose a file system. Redmi 9 is best suited for exFAT or FAT32. Start the process and wait for the message of successful completion.
After formatting, a third-party application recommends that you remove the flash drive through the notification menu (“Secure Retrieval”) and reconnect it, which will allow the MIUI system to re-index the file system and correctly display the available space. If errors occur after that, it may be physically damaged.
Expanding Internal Memory (Virtual Memory)
Owners of Xiaomi Redmi 9 versions with a small amount of internal memory (32 or 64 GB) may want to use the flash drive as an extension of internal memory. This feature in Android is called “Adoptable Storage”, which allows you to install applications directly on the flash drive, freeing up space in the system.
However, in the MIUI shell, this feature is often hidden or completely disabled by the manufacturer. The standard formatting menu suggests using the flash drive only as Portable Storage. To activate the ability to use as Internal Storage, special commands may be required via ADB (Android Debug Bridge) from the computer.
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Using a flash drive as internal memory reduces the overall speed of the smartphone, as the speed of reading / writing USB-The storage is usually lower than the internal memory eMMC/UFS.
To activate via ADB, you need to connect your phone to your PC, enable USB debugging, and type in the sm partition command. This is a complex process that requires accurate knowledge of the disk ID. Once the command is successfully executed, the flash drive will be formatted into an encrypted format that is only available to that particular phone.
Is it worth the sheepskin? With the Redmi 9 with its MediaTek Helio G80 processor, external memory speed can be a bottleneck. Applications can take longer to load and the system slows down. It is recommended to use the flash drive specifically for media files, leaving internal memory fast and responsive to the system and active applications.
Solving Connection Problems and Errors
Despite the simplicity of the procedure, users often encounter various errors — «USB-The device is corrupted" or a suggestion to format the disk that does not result.This often indicates logical errors of the file system that can be corrected by the error check team on the computer (CHKDSK), before reconnecting to the phone.
Another problem is that the flash drive is detected, but the files are not copied. MIUI You must manually allow the file manager to access the USB-Also make sure that the flash drive does not have a marker file that prevents recording (although modern flash drives no longer have physical switches).
- 🛑 “Not enough space” error: check if files are hidden by a virus that takes up all the space.
- 🔥 Overheating: If the phone is too hot at the contact point, interrupt the process.
- 🔌 Unstable connection: Try flipping the Type-C plug or cleaning the port with compressed air.
⚠️ Note: If the flash drive stopped being detected on all devices (PC, TV, other phones) after trying to format on Redmi 9, it may be that the memory controller failed due to a voltage surge.
If nothing works, and the flash drive doesn't work in any device, it may require low-level formatting with special utilities on a PC, such as the HP USB Disk Storage Format Tool or the SD Memory Card Formatter. These programs are able to restore factory markup, ignoring standard operating system errors.