OTG on Xiaomi Redmi 9A: how to turn on and use – full instruction

Why can’t the Redmi 9A run OTG out of the box?

Owners of the budget smartphone Xiaomi Redmi 9A Often faced with a problem: connect USB-flash-drive OTG-The adapter, and the device can't see them, and it's not because of hardware constraints. G25 redmi 9A technically supportive OTG, but the default function is disabled at the software level.

The manufacturer saved on firmware for the budget model by removing the explicit OTG switch from the interface. However, activation is possible through hidden settings or third-party utilities. In this article, we will analyze all working methods from standard to alternative, including solving typical errors like “Device not recognized” or “No power”.

Important: Before setting up, check the adapter's compatibility.Redmi 9A demand OTG-cable USB 2.0 Type-C (not to be confused with Micro-USB!) More information about adapter selection is in the section below.

How to check if your Redmi 9A OTG is supported?

Before you try to turn on the feature, make sure your device supports it. Even within the same Redmi 9A model, there may be regional differences in firmware. Here are 3 ways to check:

• 🔍 Through the app USB OTG Checker: install it from Google Play and run the test. the app will show whether the smartphone recognizes connected devices.
• 🔌 Test connection: knowingly take a working OTG-adapter and flash drive (formatted into FAT32), If the flash drive lights up, there's support, it's off.

If none of these methods worked, you may have been stripped down by the manufacturer, and then only flashing it to a custom version (like LineageOS) will help, but it's risky for beginners.

Method 1: Enabling OTG through hidden developer settings

The safest method is activation through the developer menu, which is hidden by default, but it's easy to open:

1. Go to Settings. → The phone.
2. Find the MIUI version and tap it 7 times in a row (you will receive a notification “You became a developer”).
3. Return to the main settings menu – there will be a new section for developers.

Now you need to find the OTG setting:

• Open for developers → USB configuration.
• Select File Transfer Mode (MTP) or USB-modem (RNDIS) — This indirectly activates support. OTG.
• Connect. OTG-If the device is undecided, restart the smartphone.

Battery charge > 30%|Used by the original OTG-adapter|The flash drive is formatted in FAT32|Developer mode is on-->

⚠️ Attention: after activation OTG You might see a warning on the developer menu about increased power consumption, which is normal, because when you connect external devices, the smartphone consumes additional energy.

Method 2: Use of the OTG Assistant application

If the standard settings didn’t help, install a third-party utility. OTG Assistant (available on Google Play) automatically checks for OTG support and tries to activate it through system calls.

Instructions:

1. Download and install the OTG Assistant.
2. Launch the app and press Check OTG.
3. If support is available but disabled, tap Enable OTG (ADB rights required).
4. Connect. OTG-device and wait for identification.

The app also shows the current voltage on the USB-port (should be) ≥ 4.5V). If the voltage is lower, the problem may be a faulty adapter or port.

Method 3: Manual editing of a configuration file (for advanced ones)

This method requires root rights and is designed for users willing to risk the stability of the system. If you're a beginner, skip this section.

Instructions:

1. Install Root Explorer or any file manager with root access.
2. Go to /system/etc/permissions/.
3. Find the file android.hardware.usb.host.xml.
4. Open it in the text editor and add the line: <feature name="android.hardware.usb.host" />
5. Save the file, restart the device.

Once rebooted, the OTG should be up and running.If the android.hardware.usb.host.xml file is missing, it can be created manually with the specified content.

⚠️ Warning: Incorrect editing of system files can lead to bootloop ( looped boot).Before changes, back up through TWRP.

Table: Device compatibility with OTG on Redmi 9A

Not all. USB-The devices will work well with Redmi. 9A through OTG. Below is the compatibility table of popular gadgets:

Critical information: if you connect a hard drive, use it OTG-externally powered hub.Redmi Port 9A does not provide sufficient current for HDD, Which can cause damage to the file system.

Solving Common Problems with OTG

If the OTG does not work even after activation, check these points:

• 🔋 Insufficient power: connect the charger in parallel with OTG-Some flash drives require more power than the port can deliver.
• 🔄 Firmware conflict: Update MIUI Up to the latest version through Settings → Updating the system.
• 🛠️ Damaged port: Check the Type-C connector for contamination or mechanical damage.
• 📱 Antivirus Block: temporarily disable Google Play Protection or Third Party Antivirus.

If the smartphone makes a mistake «USB-The device is not recognized, try it:

1. Disconnect and reconnect OTG-adapter.
2. Reboot the phone with the flash drive connected.
3. Format the flash drive in FAT32 on PC.

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If the OTG is unstable, try using a ferrite ring adapter – it suppresses interference and stabilizes the connection.

FAQ: Frequent OTG questions on Redmi 9A