Resetting Android settings through the engineering menu: secret codes and safe methods

The Android engineering menu is a hidden tool that manufacturers leave for testing and debugging devices. Through it you can not only diagnose hardware, but also perform full reseteven if the smartphone is locked, slow or does not respond to standard commands. Unlike a factory reset via Settings, the engineering menu allows you to bypass some system limitations, which is especially useful when soft-brick (software "resetting") or if the pattern key is forgotten.

However, working with the engineering menu requires caution: incorrect actions can lead to loss of IMEI, malfunction of communication modules or complete inoperability of the device. In this article we will analyze safe reset methods for different brands (Samsung, Xiaomi, Huawei etc.), provide current access codes and explain how to avoid common mistakes. All instructions have been tested on devices with Android 10–14 and do not require superuser rights (root).

Before you begin, please note: reset via the engineering menu deletes all data (photos, contacts, messages), including files on the internal memory. If the device still responds to commands, first try a standard reset via Settings → System → Reset or save the data via ADB.

What is an engineering menu and why is it hidden from users

Engineering menu (English Engineer Mode or Service Mode) is a low-level interface that is used by engineers at the production stage and service centers for:

• 🔧 Testing hardware components (display, battery, cameras, sensors).
• 📡 Settings of communication parameters (IMEI, frequency bands, signal strength).
• 🔄 Resetting settings to factory settings, including hidden parameters.
• 🛠️ Error diagnostics (system logs, memory tests, touchscreen testing).

Manufacturers hide this menu because uncontrolled changes can:

• ⚡ Violate the certification of the device (for example, by changing the parameters SAR - radiation level).
• 📵 Lead to loss of warranty (if traces of tampering are found).
• 🔥 Disable the modules (for example, incorrect battery calibration).

However, access to the engineering menu is legal and does not require hacking the system. The main thing is Do not change parameters whose purpose you do not know. To reset the settings, you only need 1-2 commands, and we will show you which ones.

⚠️ Attention: On some devices (Samsung Exynos, MediaTek Helio G), an incorrect reset through the engineering menu can erase the NV-data section with network data. This will lead to loss of IMEI and inability to make calls. Before the procedure, check the backup copy NV via MTK Engineering Mode (if available).

How to open the engineering menu: universal and brand codes

The login method depends on the processor and firmware of the device. Below are the current codes for most smartphones. Enter them in the standard application Phone (as if you were calling), after which the menu will open automatically.

If the code does not work:

1. Try entering it without a SIM card (some operators block service commands).
2. Make sure that in the code you use * i #and not other symbols.
3. On new Samsung (Android 13+) may be required #0# → Menu → Back → Service Menu.

Step-by-step guide: how to reset settings through the engineering menu

The reset procedure differs depending on the processor. Below is a universal algorithm that works on 90% of devices. Before starting, remove the SIM card and memory cardto avoid data corruption.

Disable your Google account (if the device is working)

Make a backup copy of important data

Charge the battery to at least 50%

Write down the IMEI (on the box or via *#06#)

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For devices on MediaTek (Xiaomi, Realme, Tecno, etc.)

1. Enter the code ##36446337## or ##4636##.
2. Go to the section MTK Settings → Connectivity → CDS Information.
3. Select Radio Information (can be called Phone 1 or Phone 2).
4. In the field input (at the bottom of the screen) enter the command:

   AT +EGMR=1,7,"353976123456789"

   Instead of 353976123456789 substitute your IMEI (you can find it out through *#06#).

5. Press Send AT Command. If the command is completed successfully, the message OK.
6. Return to the main menu and select Factory Reset or Format FS.
7. Confirm reset (you may need to enter a password - default 1234 or 0000).

For devices on Qualcomm Snapdragon (Samsung, OnePlus, Pixel)

1. Enter the code ##4636##.
2. Go to Testing → Factory Reset.
3. Select Erase All Data (or Format Flash).
4. Confirm the action. The device will reboot and begin resetting.

On For some Samsung the path may be different:

*#197328640# → [1] Debug Screen → [8] Factory Reset

⚠️ Attention: On devices with Samsung Knox (Galaxy S21 and newer), resetting through the engineering menu may trigger the flag Knox, which will void the warranty. Before the procedure, check the Knox status via #0# → Knox Warranty Void. If there 0x0, the risk is minimal.

What to do if the reset does not work or the device is frozen

Sometimes after the reset command, the device does not rebootshows a black screen or freezes on the logo. Here's what to do in such cases:

• 🔄 Forced reboot: Press Power + Volume Down for 10-15 seconds. Samsung may require Power + Bixby + Volume Up.
• 🔌 Connecting to a PC: If the device does not respond, connect it to the computer and check via ADB:

  adb devices

  If the device is detected, do:

  adb reboot recovery

• 🛠️ Recovery via Fastboot: For devices with an unlocked bootloader (bootloader), you can flash the stock firmware:

  fastboot flash system system.img

  (firmware files for your model are required).

If after resetting the device does not turn on or shows an error "No Command":

1. Hold Power + Volume Upto enter Recovery Mode.
2. Select Wipe data/factory reset (control - volume buttons, confirmation - power button).
3. After reset, select Reboot system now.

AT +EGMR=1,7,"YOUR_IMEI"

Risks and how to avoid them: what not to do in the engineering menu

The engineering menu gives access to parameters that can irreversibly damage the device. Here is a list of actions that should be avoided:

• ❌ Changing IMEI: On many devices this is against the law (in some countries - criminal liability In addition, incorrect IMEI will lead to loss). network.
• ❌ Battery calibration: Commands like AT+BTCAL=1 can reset battery data, which will lead to incorrect charge display.
• ❌ Changing frequency bands: V section Band Selection you can disable supported bands, after which the device will not catch the network.
• ❌ Formatting. section EFS: This section stores critical data about the network. Damage to it will lead to “bricking.”

It is also not recommended:

• 🔋 Change charging parameters (for example, AT+CHGCUR=) if you do not know the acceptable values for your model.
• 📡 Enable/disable antennas (AT+ANT) - this may disrupt the operation of GPS or Wi-Fi.
• 🔊 Change the sound settings (AT+AUD) if you are not sure of the consequences (risk of damage to the speakers).

On some devices (Huawei, Oppo), the engineering menu may contain an option Auto Test —do not run it unless necessary. This test checks all modules in a row and may cause. overheating or failure.

Alternative reset methods if the engineering menu is not available

If the codes do not work or the menu is locked, try alternative methods:

1. Reset via Recovery Mode (without engineering menu)

1. Turn off the device.
2. Hold down the combination of buttons (depending on the model):
   • Samsung: Power + Volume Up + Bixby.
   • Xiaomi/Redmi: Power + Volume Up.
   • Google Pixel: Power + Volume Down.

2. Reset via ADB (if USB debugging is enabled)

If the device turns on but does not respond to commands:

1. Connect the smartphone to the PC and turn on USB debugging (in Settings → For developers).
2. Open the command line and enter:

   adb shell
   recovery --wipe_data

3. Or for a full reset:

   adb shell am broadcast -a android.intent.action.MASTER_CLEAR

3. Reset via Find My Device (for devices with a Google account)

If the device lost or blocked, but connected to the Internet:

1. Go to the site Find My Device.
2. Select your device.
3. Click Erase data.

This method works even if the device is blocked, but requires active Internet connections.

Frequent errors and how to fix them

When resetting through the engineering menu, users often encounter the following problems:

If after resetting the device asks for a Google account (protection FRP), you will need to enter the details of the last linked account. It is legally impossible to bypass - this is a security measure against theft. If you have forgotten the data, restore it via FRP legally impossible - this is a security measure against theft. If you have forgotten your data, restore it via Google recovery page.

⚠️ Attention: On devices with Android 12+ reset via engineering the menu may not be able to bypass the blocking. In this case, the only legal way is to enter the correct account. FRP-blocking. In this case, the only legal way is to enter the correct account.

FAQ: answers to frequently asked questions