OTG on Xiaomi Redmi Note 9: how to turn on and use flash drives / mouse

The OTG (On-The-Go) feature on the Xiaomi Redmi Note 9 allows you to connect USB drives, keyboards, mice and even game controllers to your smartphone through a standard USB-C connector. Despite the obvious utility, many users face problems when connecting for the first time: the device is not detected, errors appear or the function is completely absent from the menu. In this article, we will analyze all the ways to enable OTG, from basic settings to hidden developer parameters, and also tell you how to check the compatibility of your Redmi Note 9 with specific accessories.

It’s important to understand that OTG support is not only software-related, but also hardware-related. For example, some Xiaomi budget models may not provide enough current to power 2.5 hard drives or external SSDs. We tested OTG on Redmi Note 9 (M2003J15SC and M2003J15SS) with MIUI 12.5-14 firmware – all of the methods described are relevant for these versions. If your smartphone is running on custom firmware (for example, LineageOS or Pixel Experience), some instructions may differ.

What is OTG and why you need it on the Redmi Note 9

USB On-The-Go (USB OTG) technology turns your smartphone into a full-fledged host device capable of managing the periphery. In practice, this means that the Redmi Note 9 can:

• 📁 Read and write files to flash drives (FAT32/NTFS/exFAT) computer-free.
• 🖱️ Connect a mouse or keyboard for easy text input (useful for working with documents).
• 🎮 Use gamepads (such as Xbox or DualShock) for mobile games.
• 📷 Import photos from cameras or card readers.
• 🔊 Connect external sound cards or MIDI-devices (for musicians).

However, there are limitations, such as the Redmi Note 9 will not be able to power devices that require more than 500 mA (such as some portable hard drives without external power), and not all file systems are supported out of the box: to work with NTFS, you may need to install additional applications such as Total Commander or USB OTG Helper.

The USB-C connector on the Redmi Note 9 supports USB 2.0, so the maximum read/write speed is around 40-50MB/s (depending on the flash drive), which is faster than the microSD cards in the smartphone slot, but slower than USB 3.0 on a PC.

How to check if your Redmi Note 9 supports OTG

Before you buy an adapter or cable, make sure your smartphone hardware supports OTG. There are several ways to check:

1. All versions of the Redmi Note 9 (including Note 9 Pro, Note 9S, Note 9T) officially support OTG. Except for models for some regions (for example, the Indian version of the M2003J15PI may have limitations).
2. Install the USB OTG Checker utility from Google Play, which will show you if the feature is available on your device.
3. Go to Settings → About Phone → MIUI Version and tap 7 times on the core line. Go back to the main settings menu and the Developer Menu will appear. Find the default USB configuration option (if any, OTG is supported).

If none of these methods worked, you may have OTG support turned off on your device at the firmware level, which is true for some custom builds or lightweight versions of MIUI (e.g. MIUI Lite), and only flashing it to the official version will help.

Step-by-step: how to turn on OTG on Xiaomi Redmi Note 9

In most cases, the OTG on the Redmi Note 9 runs out of the box, but sometimes manual activation is required.

1. Buy the right cable. You need a USB-C (male) → USB-A (female) or USB-C → USB-A cable. Avoid cheap Chinese unlabeled adapters - they may not provide a stable connection.
2. Connect the device. Put a flash drive or other accessory into the adapter, then connect to the smartphone "USB-plug-in".
3. Allow access. Swipe down the notification bar and tap on the connection message. Select "Allow data access" (if the flash drive is connected) or "Use as... (for mouse/keyboard).
4. Open the Files app (or Explorer) and your flash drive should appear in the Devices section.

If the notification does not appear:

• 🔄 Reboot your smartphone and reconnect.
• 🔌 Try another cable or adapter (defective accessory is a common cause of problems).
• 📱 Update the firmware to the latest version MIUI (In the old versions there were bugs with OTG).

Check the adapter model (must be USB-C → USB-A)

Make sure the flash drive is formatted in FAT32/exFAT

Charge your smartphone at least 30% (OTG consumes additional energy)

Turn off the others. USB-devices (if connected)

Update the Files app to the latest version-->

If after all the manipulations, the OTG still does not work, move to the next section - there are advanced configuration methods.

Advanced Settings: Enabling OTG through Developer Mode

In rare cases, the OTG can be disabled at the system level to activate it:

1. Activate Developer Mode: Settings → The phone. → Version. MIUI → Tap 7 times on the line "Version" MIUI" After that, in the main settings menu will appear item For developers.
2. Go to Settings → Additional → For developers.
3. Find the default USB configuration option and select File Transfer (MTP) or PTP (for cameras).
4. Activate the USB Debugging Switch (this can help when connecting keyboards/mouse).
5. Reboot your smartphone.

Important: some MIUI firmware may not have the USB Configuration option, in which case try resetting the network settings (Settings → System → Reset → Network Reset) – this sometimes restores hidden settings.

If after turning on the developer mode, the OTG earned, but after a while it stopped being determined again, check:

• 🔋 Battery level (at a discharge below 15% OTG can be automatically switched off).
• 📵 Active presence VPN Firewalls (they can block access to the USB-device).
• 🛠️ Security updates (in MIUI 13+ Restrictions on the connection of non-certified devices).

Compatibility table: which devices work with OTG on Redmi Note 9

Not all. USB-The device will work correctly with the Redmi Note 9 OTG. Below is a table of compatibility with popular accessories:

To connect hard drives, we recommend using a Y-cable with additional charging power, which will solve the problem of lack of current, which can cause the HDD to be undetected or disconnected after a few seconds.

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If you connect a keyboard or mouse, but they are running with delays, try turning off power saving for USB in the developer settings (the option “Do not turn off USB to save charge”).

Frequent OTG issues on Redmi Note 9 and their solutions

Even after setting up the OTG correctly, there may be failures, and let’s look at the typical errors and how to fix them:

⚠️ Warning: If the smartphone starts to warm up or discharge quickly when you connect a flash drive, immediately turn off the device. This may indicate a short circuit in the adapter or a malfunction. USB-port.

If none of the methods worked, try resetting your network settings:

1. Go to Settings → System → Reset.
2. Select Network Settings Reset (this won’t delete your data, but will reset Wi-Fi, Bluetooth, and mobile network settings).
3. Reboot your smartphone and reconnect the OTG.

In extreme cases, you may need to completely reset your settings (but make a backup copy of the data before you do!).

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If OTG It stopped working after the update. MIUI, Try to roll back to the previous firmware version via the Mi Flash Tool. in some builds (for example, MIUI 13.0.4) were bugs with USB-host.

Alternative ways of connecting USB-device

If the OTG on the Redmi Note 9 never worked, consider alternative options:

• 🌐 Cloud storage. Upload files from a flash drive to Google Drive or Mi Cloud, then download them to your smartphone.
• 📶 FTP-Install FileZilla Server on your PC and on your smartphone — FX File Explorer with support FTP. Connect to your computer via a local network.
• 🔄 Wireless transmission. For cameras, use Wi-Fi Direct or applications like Canon Camera Connect.
• ⚡ Adapters Lightning/USB-C. If you have an iPhone or iPad, you can use a Lightning adapter. → USB-A flash-reader.

For gamers who need controllers, an alternative is available. OTG Bluetooth gamepads will be used (for example, 8BitDo Pro 2 or Razer Kishi. They connect directly wirelessly and are independent of support. USB-host.

If you need to work with external drives regularly, consider buying a router with a USB-port (for example, TP-Link) TL-MR6400). Connect the flash drive to the router, and then access the files through the local network from the smartphone.

FAQ: answers to frequent questions about OTG on Xiaomi Redmi Note 9