USB debugging Android 9 Pie is a bridge between your smartphone and your computer, which allows access to advanced functions: firmware flashing, data recovery, application testing, and even crash repair. Without this mode, it is impossible to use ADB, Fastboot or tools like Odin for Samsung and SP Flash Tool for Mediatek. But manufacturers hide this option deep in the menu - and for good reason: wrong actions can turn the phone into a “brick.”

In this article you will find step-by-step guide taking into account the characteristics of different brands (from Xiaomi to Google Pixel), a table of cable compatibility, as well as solutions typical errors like “device not detected”. We will look at why debugging sometimes turns off by itself, how to bypass the blocking on some firmware, and what to do if the computer does not see the phone even after all the manipulations. There is no need to look for a video on YouTube - everything is laid out here, with pictures and warnings about pitfalls.

⚠️ Important: The procedure for activating USB debugging is identical for most devices on Android 9, but some manufacturers (for example, Huawei or OnePlus) can make changes to the interface. If your model was released after 2022, check the relevance of the instructions in the official documentation of the brand.

1. Preparation: what needs to be done before enabling debugging

Before going into the settings, make sure that your computer and phone are ready to “communicate”. By skipping this step, you risk spending hours trying to find the reason why adb devices returns an empty list.

First, check USB cable. Yes, even if it's charging your phone. Cheap cables often do not transmit data - only power. Use the original cable from your smartphone or a certified one USB Type-C/Micro-USB with support USB 2.0 or higher. Suspect the problem is with the cable? Connect your phone to another USB port on your computer - sometimes faulty connectors are to blame.

Secondly, install drivers. Without them, Windows (and macOS/Linux) will not recognize the device as a debug one. For most brands, a universal package is suitable Google USB Driver, but for Samsung you need Samsung USB Driver for Mobile Phones, and for Xiaomi — Mi PC Suite. Download drivers only from official websites!

  • 🔌 Cable: Original or certified (for example, Anker, Belkin). The length is no more than 1 meter - long cables lose the signal.
  • 💻 Drivers: For Windows — Google USB Driver + branded brand drivers. On macOS/Linux usually the standard ones are enough.
  • 🔄 Connection mode: On the phone, when connecting to a PC, select File transfer (MTP)rather than Charging only.
  • 🛡️ Antivirus: Temporarily disable it - some apps block adb.exe as a suspicious file.
📊 What brand of your smartphone?
Samsung
Xiaomi
Huawei
Google Pixel
OnePlus
Other

2. Step-by-step guide: how to enable USB debugging on Android 9

Now let's move on to the main thing. Enabling USB debugging consists of two stages: unlocking the developer menu and activating debugging itself. Follow the instructions carefully - skipping a step may lead to errors.

📌 Step 1. Open the developer menu

It is hidden by default. To unlock it:

  1. Go to Settings → System → About phone (on some devices the path may differ: Settings → About device).
  2. Find line Build number (or Build number).
  3. Click on it 7 times in a row. After 3-4 clicks, the notification “You are almost there!” will appear, and after the 7th - the message “You have become a developer!”.

📌 Step 2. Enable USB debugging

Now a new item will appear in the main settings menu For Developers (or Developer optionsOpen it and:

  1. Scroll down to section Debugging.
  2. Activate the switch USB Debugging (or USB debugging).
  3. In the confirmation window that appears Click OK or Allow.

📌 Step 3. Connect the phone to the computer

Do this After enable debugging. When you connect for the first time, a request will appear on the phone screen to trust this computer. Be sure to check the “Always allow from this computer” checkbox and click “Allow” - otherwise you will have to confirm the connection every time.

Developer menu enabled | Software debugging activated USB|Drivers are installed on the PC|The original cable is used|MTP mode is selected when connecting-->

3. Features for different brands: Xiaomi, Samsung, Huawei and others

Manufacturers like to “improve” Android, so the path to debugging may differ. Here is what owners of popular brands need to know:

Brand Features of the path to the developer menu Additional nuances
Xiaomi Settings → About phone → MIUI version (press 7 times) On some models (Redmi Note 8, POCO X3), you are required to enter your account password Mi to confirm.
Samsung Settings → Phone information → Software information → Build number On Galaxy S9/S10 c One UI the developer menu can be called Developer options.
Huawei/Honor Settings → System → About phone → Build number On firmware EMUI 9.x You may need to enter a PIN code or pattern.
Google Pixel Settings → System → About phone → Build number Debugging is the most stable - Google does not block ADB commands.
OnePlus Settings → System → About the phone → Build number On OxygenOS the developer menu is called Developer mode.

⚠️ Attention: On devices Huawei with firmware EMUI 10+ (released after 2019) may require additional permission in the Security → Advanced settings → Allow HiSuite debuggingsection. Without this, ADB will not work.

💡 Advice for owners Samsung: If, after connecting to a PC, the phone displays the error “USB device is not recognized,” try installing Samsung Smart Switch —it will automatically install the necessary drivers.

4. Checking debugging: ADB commands and common errors

You have enabled debugging, but how can you make sure that everything is working? Open Command Prompt (or Terminal on macOS/Linux) and run the following commands:

📌 Step 1. Check connections

adb devices

If debugging works, you will see the device serial number in the list. If the list is empty, something went wrong.

📌 Step 2. Test command

adb shell getprop ro.build.version.release

This command should return the Android version (in your case - 9If you see it instead). error device unauthorized or no devices/emulators found, read the section below.

🔍 Deciphering ADB errors:

  • 🚫 device unauthorized → The phone is not trusted to the computer. Disconnect and reconnect the cable, unlock the screen and enable debugging.
  • 🔌 no devices found → Problem with drivers, cable or USB port. Try another port or cable.
  • 🔄 offline → The device is connected, but there is no ADB daemon. Reboot the phone and repeat adb kill-server → adb start-server.
What to do if ADB does not see the device, although debugging is enabled?

1. Reinstall the drivers manually via Device Manager (Windows).

2. Check if your antivirus or firewall is blocking debugging.

3. Try connecting from another computer - this will help localize the problem (on your phone or PC).

4. On some firmware (for example, ColorOS from Oppo), you need to enable OEM Unlock in the developer menu.

5. Security: risks of USB debugging and how to minimize them

USB debugging is not only opportunities, but also vulnerabilities. With its help, an attacker can:

  • 📱 Install malware without your knowledge.
  • 🔓 Gain access to personal data (photos, messages, passwords).
  • 🚨 Completely erase data or block the device.

⚠️ Attention: Never connect a phone with debugging enabled to public USB ports (in airports, cafes, shopping centers). Attackers can use them for an attack BadUSBwhen the device emulates a keyboard and executes commands on your behalf.

🔐 How to protect yourself:

  1. Disable debugging when not needed (developer menu → turn off USB debugging).
  2. Use lock screen (PIN, pattern or fingerprint). Without it, anyone can connect to the phone via ADB.
  3. Set Always request permission in the developer menu (if there is such an item).
  4. For critical operations (firmware, unlocking the bootloader) use separate computerwhich does not store personal data.

💡 Tip: If you often work with ADB, create a separate user on the computer with minimal rights. This will reduce the risk of infection of the system if a virus gets on the phone.

6. what to do?

Sometimes there is a developer menu, but the switch USB debugging is inactive or immediately disabled. Here are the most common causes and solutions:

Problem Possible cause Solution
Gray debug switch Corporate policy restriction (for example, on work phones) Contact your administrator or reset settings to factory.
Debugging turns off itself The option is active Disable debugging when connected to Wi-Fi (rarely) Check the developer menu for such items.
There is no “For Developers” item The menu is not unlocked (clicked less than 7 times on Build number) Repeat the clicks or reboot the phone.
When turned on debugging asks for a password Account protection is activated (for example, Mi Account on Xiaomi) Enter the password for the manufacturer's account.

🔧 Radical solution: If debugging is blocked by a virus or a firmware failure, it may help reset to factory settings. But remember: this will delete all data from the internal memory! First make a backup copy via adb backup (if debugging works at least sometimes) or manually copy the files to the PC.

📌 For owners Samsung: If debugging does not turn on after updating the firmware, try resetting the APN settings. Sometimes this helps to regain access to hidden functions Path: Settings → Connections → Mobile networks → Access points (APN) → Reset.

💡

If USB debugging does not turn on, 90% of cases are to blame: an unlocked developer menu, lack of drivers on the PC, or blocking by an antivirus.

FAQ: Frequently asked questions about USB debugging on Android 9

❓ Is it possible to enable USB debugging without access to the settings (for example, if the phone is locked)?

No, if the screen is blocked, it is impossible to enable debugging using standard methods. The only option is to use recovery mode (Recovery Mode) or (Recovery Mode) or Fastboot, but for this, debugging must already be activated earlier. If you did not enable it in advance, you will have to reset the phone to factory settings (data loss!). data-i="235">❓ Why does the computer not see the phone, although debugging is enabled?

❓ Why doesn’t the computer see the phone even though debugging is enabled?

There are several reasons:

  • The drivers are not installed (check Device Manager for exclamation marks).
  • USB cable does not support data transfer (try another one).
  • The phone is not trusted to the computer (a window with a request should appear when connecting).
  • ADB server is not running (run adb start-server in the command line).
❓ Do I need to enable OEM Unlock for debugging to work?

No, OEM Unlock it is only needed to unlock the bootloader (for example, before flashing a custom recovery) For standard USB debugging, it is not necessary to enable it. (for example, OnePlus) without it, ADB can work with restrictions.

❓ How to disable USB debugging remotely if the phone is stolen?

Unfortunately, this is not possible using standard Android tools. But you can:

  • Lock the device remotely. via Google Find My Device.
  • Erase data (also via Find My Device), but this will delete everything, including photos.
  • If your phone was turned on Samsung Knox or Mi Cloud, use their locking functions.

In the future, configure device encryption and bootloader lock - this will make it difficult for attackers to access data even through ADB.

❓ Works Is this instruction for Android 10/11/12?

The main steps (unlocking the developer menu and enabling debugging) are identical, but may differ:

  • Path to Build number (for example, in Android 12 this Settings → About phone → Software information).
  • Additional permission requests (for example, confirmation by PIN code each time you connect).
  • Restrictions for third-party firmware (on Android 11+ Google has tightened the rules for working with memory partitions via ADB).

For new versions of Android, look for up-to-date guides - some functions (for example, adb backup) may be disabled.