Developer mode on Xiaomi Redmi 9 gives you access to hidden Android features that allow you to fine-tune the system, test applications and even install alternative firmware. But it’s not just a tick in the settings, it’s the first step to full control of the device, which requires caution and understanding the consequences. Many users confuse the developer mode with unlocking the bootloader or obtaining root rights, although these are different processes with different levels of risk.
In this article, we will learn how to safely activate the hidden capabilities of Redmi 9 (model M2003J15SC/M2003J15SS), what tools you will need to do this, and what to do if something goes wrong. You will learn how to circumvent the limitations of MIUI, why Xiaomi blocks some functions by default, and what 3 critical errors lead to a “brief” of the device in 90% of cases of failed manipulations.
We warn you right away: you do everything at your own risk. Xiaomi warranty is canceled after unlocking the bootloader, and improper manipulation can turn your smartphone into a brick. If you are a beginner, start with secure features of the developer mode, without touching unlock or firmware.
1. Activate Developer Mode on Redmi 9
The developer mode is hidden in MIUI for a reason: it's designed for testing and debugging, not everyday use. To turn it on, follow a simple sequence of steps:
- Open the Settings. → The phone.
- Find the MIUI version string and tap it 7 times in a row.
- After the notification “You became a developer!”, return to the main settings menu.
- Now in the settings will appear a new section Additional → For developers.
In this section, you’ll find dozens of options, from USB Debugging to Secondary Display Emulation, but beware: changing some options (like Don’t Turn Off the Screen or Background Limit Process) can cause the battery to overheat or run out quickly.
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If the Developer For section disappeared after the MIUI update, repeat the activation procedure again – sometimes the system resets this flag.
Among the most useful features for ordinary users:
- 🔄 Windows animation – speeding up or turning off animations for fast work.
- 📱 Emulation resolution - change DPI for a more compact display of the interface.
- 🔋 Background processes – a limitation to battery saving (but can close down desired applications).
- 🔌 Debugging by USB — mandatory for work with ADB and unlock the loader.
2. Unlock the bootloader: preparation and risks
If you need to install custom recovery (like TWRP) or alternative firmware (like LineageOS), you first need to unlock the bootloader. Xiaomi officially allows this, but the process comes with a number of limitations:
⚠️ Warning: Unlocking the bootloader completely resets all data on the device, including photos, contacts and apps, it also voids the warranty and may block some features MIUI (For example, Mi Pay or Find Device).
To unlock, you will need:
- 📱 Smartphone Redmi 9 with battery charge > 60%.
- 💻 Windows computer (official Xiaomi software does not support) macOS/Linux).
- 🔌 Original. USB-cable (cheap cables can interrupt the connection).
- 🔑 Mi Account with a linked phone number (required for confirmation).
The unlocking process takes 72–168 hours (3–7 days) due to Xiaomi’s policy.
| Phase | Duration | What's going on? |
|---|---|---|
| Request for permission | Instantly. | Submit your application via Mi Unlock Tool. |
| Waiting for SMS | 5-30 minutes | Confirmation code for the linked number. |
| Waiting to unlock | 72-168 hours | Xiaomi servers check the account. |
| Final unlock | 10-20 minutes | Connecting the phone to the PC and executing the command. |
If you are in a hurry, there are informal methods of bypassing the wait (for example, through the use of a slug). EDL-Mode), but they require you to buy an authorized Xiaomi account or exploit vulnerabilities that can lock the device.
3. Installation of TWRP and obtaining root rights
After unlocking the bootloader, you can install custom recovery TWRP (Team Win Recovery Project, which will allow you to create backups, sew ZIP-Files and root access through Magisk.
For Redmi 9, TWRP 3.7.0 from mauronofrio (check the relevance on the XDA Developers forum) is suitable.
fastboot flash recovery twrp-3.7.0-juice.img
fastboot boot twrp-3.7.0-juice.imgImportant: after installing TWRP, you must immediately flash Magisk or Disable Force Encryption, otherwise, the first reboot MIUI will re-run custom recovery!
Download the official TWRP image for Redmi 9| Check the fastboot version (should be ≥ 31.0.3) | Turn off encryption in the MIUI settings | Create a backup on PC | Prepare the Magisk.zip file on the memory card-->
Root rights give you complete control over the system, but have the opposite side:
- ❌ Ban in games (e.g. ban in games, PUBG Mobile or Genshin Impact will be found root).
- ❌ Problems with banking applications (Sberbank, Tinkoff, etc. block work).
- ❌ Security risk – malware can access system files.
How to get around the ban in games with root rights?
4. Installation of custom firmware: MIUI vs AOSP
Redmi 9 can be used in two categories:
- MIUI-firmware (e.g. firmware, MIUI EU China Stable – modified versions of the official shell.
- AOSP-Firmware (e.g. LineageOS, Pixel Experience) – “clean” Android without MIUI.
MIUI-Firmware retains all Xiaomi features (e.g. Second Space or Game Turbo), but may contain a bloatwar (pre-installed apps). AOSP-Firmware is devoid of this, but lose support for some gestures and branded chips.
| Parameter | MIUI (EU/China) | AOSP (LineageOS) |
|---|---|---|
| Stability | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ (Possible camera bugs) |
| Productivity | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ (less-ground) |
| Camera support | ⭐⭐⭐⭐⭐ (full-fledged) | ⭐⭐ (required by GCam) |
| Updates | Weekly/monthly | Every 1-3 months |
For custom firmware installation:
- Download. ZIP-Firmware file and place it on a memory card.
- Boot to TWRP (hold Power + Volume up when turned on).
- Run Wipe → Format Data (this will delete everything, including internal memory!).
- Please. ZIP-Firmware file, then Magisk (if root is needed).
⚠️ Attention: Firmware AOSP Redmi 9 can cause Wi-Fi or module to fail NFC (If you have it in your modification, check the reviews before installing it. 4PDA or XDA concretely.
5. rollback to official firmware and restoration of warranty
If you want to return an official MIUI (for example, to sell a phone or restore a warranty), you can do this through the Mi Flash Tool.
- 📁 Official Fastboot Firmware Image for Redmi 9 (download from official website).
- 🔧 Mi Flash Tool (version 2020.3.14.0 or later).
- 🔄 Regime. EDL (if the phone doesn't turn on).
Recovery process:
- Unpack the downloaded firmware image in a folder without spaces in the title.
- Connect your phone in Fastboot mode (hold Volume Down + Power).
- In the Mi Flash Tool, select the firmware folder and click Refresh → Flash.
- Wait for the finish (5-10 minutes). The phone will reboot from a clean MIUI.
To return the guarantee, it is necessary:
- 🔒 Block the bootloader back (via the Mi Unlock Tool, but it is not always possible).
- 📱 Drop it. FRP (Factory Reset Protection via fastboot oem clean_frp.
- 🔄 Make sure that in the settings → The phone. → The condition of the device is "Official".
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Even after returning to the official firmware, Xiaomi can determine that the bootloader has been unlocked, in which case the warranty will not be restored.
6 Solving Problems After Manipulation
If something goes wrong after unlocking or firmware, here are the most common problems and solutions:
| Problem. | Possible cause | Decision |
|---|---|---|
| Phone not turned on (black screen) | Incorrect firmware or interrupted process | Switch through EDL with the Mi Flash Tool. |
| Constant reboots (bootloop) | Magisk module conflict or wrong wipe | Remove all Magisk modules or reflash the firmware. |
| The sensor does not work after the firmware | Incompatible version of TWRP or firmware | Switch the correct version of TWRP for your model. |
| Wi-Fi/Bluetooth is not included | There are no drivers in the custom firmware | Swipe the kernel (boot.img) from the official MIUI. |
If the phone has become a hard brick, even if the Fastboot is not defined, there is only one way out: through EDL (Emergency Download Mode) firmware.
- 🔧 Qualcomm HS-USB QDLoader 9008 driver (install via Zadig).
- 📁 Firmware in.mbn or.elf format.
- 💻 Mi Flash Tool or QFil.
⚠️ Attention: Firmware through EDL Without an authorized account, Xiaomi can lock the device forever (an error will appear). SLA Auth Fail – Xiaomi tightened control of the system in 2026 EDL-In the service, it is better to contact the service center.
7.Unlocking Alternatives: What You Can Do Without Risk
Not everyone needs root rights or custom firmware.If you just need more options to customize Redmi 9, consider these safe alternatives:
- 🔧 ADB-commands without root: you can turn off advertising in MIUI, change DPI Or enable Dark Mode for all applications via the command: adb shell settings put global force_dark 1
- 📱 Applications with advanced settings: MacroDroid (automation), Tasker (scripts), Island (application isolation).
- 🔄 MIUI Hidden Settings: Enter #4636## to open the test menu (battery, network, etc.).
- 🔒 Encryption of data: enable in Settings → Additionally. → Encryption to protect files (but it will slow down).
To remove pre-installed applications (bloatwar) without root, you can use:
adb shell pm uninstall -k --user 0 com.mi.globalminusscreen
adb shell pm uninstall -k --user 0 com.xiaomi.midropA list of uninstall packages can be found on forums, but be careful – removing system applications can disrupt MIUI.