Modern smartphones like the Xiaomi Mi 9T have long been full-fledged multimedia centers, but their potential is often limited by internal memory. USB On-The-Go technology allows you to turn your gadget into a hub to which you can connect external drives, keyboards, mice and even game controllers. Owners of the Mi 9T model often wonder where to find the switch of this feature in the menu, since the MIUI interface has its own features.
Fortunately, unlike older versions of Android or custom builds, the current firmware for the Redmi K20 Pro (global version of the Mi 9T) supports external devices at the hardware level. This means that you do not need to search for hidden engineering menus or obtain superuser rights.
However, even with technical capability, users sometimes face a situation where the flash drive is not readable and the keyboard does not give signs of life. Most often, the problem lies not in the lack of function, but in the file system format or power shortage. In this article, we will discuss in detail how to set up the connection, which cables to use and what to do if the device does not respond to the periphery.
Technical features USB-port 9T
Xiaomi Mi 9T has a USB Type-C port that complies with the 2.0 standard but supports high-speed data transfer. It is important to understand that the physical connector is only an interface that is responsible for the power controller and software. The Snapdragon 730 hardware platform installed in this model fully supports the OTG protocol.
The main feature of the implementation in the MIUI shell is the absence of an explicit switch in the standard settings menu. Many users are used to seeing the item "Enable OTG" in the "Additional" section, as is done in OPPO or Vivo smartphones. In the case of the Mi 9T, the system works on the principle of "Plug and Play": if the device is compatible, it activates automatically when connected.
The smartphone port can provide limited current to power external devices. If you plan to connect energy-intensive gadgets such as external hard drives (HDDs) without its own power, the built-in battery charge may not be enough to start them.
⚠️ Note: Do not try to connect devices requiring voltages above 5 volts without using active USB-This can cause port protection to work or damage to the charge controller.
For stable operation, it is recommended to use an original adapter or quality cable from proven brands. Cheap Chinese adapters often have poor contact brazing, which leads to unstable connection and data loss when transferring files.
Necessary cables and adapters
The quality of the physical connection plays a crucial role in the operation of OTG technology. Since the Xiaomi Mi 9T uses a Type-C connector, you will need a corresponding USB-A adapter (standard rectangular connector) or a Type-C to Type-C cable if your peripheral device supports such an interface.
There are many adapter options on the market, but not all of them are equally useful. Any good adapter will do the job to connect flash drives, but more complex devices like Ethernet adapters or sound cards require a cable with the right resistance soldering on CC contacts.
- 🔌 Xiaomi’s original adapter: The most reliable option to ensure compatibility and proper current distribution.
- 🔌 Baseus or Ugreen Cable Adapter: Quality third-party vendors, often offering dual connectors (Type-C and Micro-USB).
- 🔌 USB-Powered hub: Necessary to connect hard drives or use keyboard and mouse at the same time.
Pay attention to the length of the cable. Too long wires (over 1.5 meters) can cause a voltage drop, which will lead to reading errors or constant reconnection of the device. Short and thick cables usually provide a more stable signal.
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If you use OTG frequently, buy an adapter with a short tail. Long adapter cables are uncomfortable to carry in your pocket with your smartphone and put extra strain on the charging port.
Algorithm for connecting external devices
The process of activating the external drive on the Mi 9T is as simple as possible for developers, you do not need to climb into the settings or use third-party applications, just perform a few sequential actions to recognize the new hardware.
First, make sure the smartphone screen is unlocked. USB-port through the adapter. 1-2 Seconds in the notification curtain should appear system message about the connection USB-If you plug in a flash drive, the system automatically prompts you to open the file manager to view the contents.
☑️ Connection check OTG
In some cases, especially when connecting non-standard devices (for example, MIDI-keyboards or specialized sensors, automatic detection may not work, so you have to manually select the mode of operation. USB in the developer menu, although for ordinary flash drives and keyboards this is extremely rare.
To safely remove the device, don't just pull it out of the port. Find the notification curtain icon. USB-the drive and press "Secure extraction." This will prevent data loss if the files were written to the disk at the time of the shutdown.
File system configuration and formatting
One of the most common reasons why Xiaomi Mi 9T doesn’t see the flash drive is an unsupported file system. Android out of the box works perfectly with FAT32 and exFAT formats. However, the NTFS format, popular on Windows, may require additional software or Root rights to write data.
If your flash drive is formatted in NTFS, your smartphone will likely only be able to read files, but it won't be able to write or delete anything. For full-time work, it's recommended to reformat the drive, you can do this directly on your computer or using the phone's own functions, if it can identify the device.
| File system | Reading support | Support for recording | Max. File size. |
|---|---|---|---|
| FAT32 | Yes (indirectly) | Yes (indirectly) | 4GB |
| exFAT | Yes (indirectly) | Yes (indirectly) | No restrictions. |
| NTFS | Yeah (often) | No (no drivers) | No restrictions. |
| ext4 | Only the Root. | Only the Root. | No restrictions. |
To format directly on your phone, go to Settings → Memory (or Settings → Phone → Storage). If the flash drive is determined but not working, the system may suggest formatting it. Remember, this action will delete all data from the drive.
How to format a flash drive in exFAT on a PC
Using OTG for peripherals: keyboards and gamepads
Functional Xiaomi Mi 9T It's not just about transferring files. USB-The keyboard, you turn your smartphone into a minicomputer, which is especially useful for typing large amounts of text or managing presentations. The system automatically determines the layout, although Cyrillic may require customization in the language menu.
Gamers will also appreciate the ability to connect wired gamepads. Many console emulators (PSP, PlayStation 1) support input from external controllers. When connecting a joystick via OTG, input lag is minimal, which is critical in dynamic games.
If your Wi-Fi router is far away or the signal is unstable, the USB-to-Ethernet adapter will provide a stable wired connection at speeds up to 100 Mbps (depending on the adapter), and a new type of connection will appear in the network settings that takes precedence over wireless.
When you use a mouse, the cursor appears automatically on the screen, and you can change the speed of the pointer, and even its appearance, if you use a special launcher application, which makes navigation on the MIUI interface similar to working with a desktop operating system.
Diagnostics and Solving Connection Problems
If nothing happens when connecting the device, or an error message appears"USB-It's not supported, you need to do a diagnostic, you need to first check if the adapter is running on another device, and often the problem is that the adapter cable is the one that might be bent or oxidized.
The second important thing is energy conservation. MIUI There are aggressive energy saving settings that may limit the current supply to the USB-Try turning off power saving mode or adding a file manager to exceptions.
- 🔍 Format check: Make sure the flash drive is formatted in FAT32 exFAT.
- 🔍 Power test: If connected HDD, Try using a Y-shaped cable or powered hub.
- 🔍 Reboot: Banal smartphone reboot can reset controller errors USB.
It’s also worth checking for system updates: Early firmware versions for the Mi 9T may have encountered bugs related to compatibility of certain flash memory chips, and updating to the current version of MIUI often resolves.
⚠️ Warning: If the phone gets too hot in the charging port area when the device is connected, immediately turn off the periphery.This may indicate a short circuit in the cable or a malfunction of the plug-in gadget itself.
In rare cases, it helps to include debugging on USB. Go to Settings. → About the phone, press 7 times on "Version" MIUI", Then in the advanced settings activate "Debugging by" USB". Sometimes this forces the controller to re-interview the ports.
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90% of OTG problems on Xiaomi Mi 9T are solved by replacing the adapter with a quality one or formatting the flash drive into the exFAT file system.
Advanced features: start a PC from a flash drive
For advanced users, the Xiaomi Mi 9T offers the ability to run full-fledged operating systems from an external medium. Using emulator applications or special downloaders, you can run a lightweight Linux distribution directly from the flash drive, which turns the smartphone into a powerful terminal for programming or network administration.
There are projects that allow you to run Windows desktop applications through Wine emulation using files stored on a connected SSD. The speed in this case depends on the speed of reading a flash drive, so using USB 3.0 (if the adapter allows) will give a tangible increase in performance.
However, it is worth remembering that constantly writing large amounts of data can accelerate the wear and tear of the internal memory of a smartphone if you use it as a cache.