This comprehensive guide provides the official download links for all available stock ROM versions for the Cubot J9. The Cubot J9 was a budget photography-oriented smartphone launched in July 2020, notable for its groundbreaking Sony 13MP quadruple rear camera array with individual lens switching, distinctive gradient color variants available in Blue, Black, and Green finishes, innovative Type-C charging port implementation on a budget device, and advanced face unlock biometric authentication system. If your device is stuck in a bootloop, experiencing software glitches like quadruple camera lens switching malfunctions between macro/depth sensors, Type-C charging port connection instability causing intermittent charging, face unlock authentication sensor failures requiring multiple recognition attempts, or has been soft-bricked, flashing the stock firmware is the ultimate solution.
This package contains the original Stock Android 10 software optimized for the MediaTek MT6580 legacy architecture. Reinstalling the firmware via the SP Flash Tool will perform a complete system restoration, resolving deep-seated software conflicts specific to the quadruple camera switching algorithms and Type-C port power management. It is the most effective method to unbrick a Cubot J9 and restore it to its original manufacturer specification. We have listed all available firmware versions below; please read the recommendations in the table for guidance on addressing your specific camera or charging port hardware configuration issues.
User Data Advisory for the Cubot J9
Critical Pre-Flash Warning: This flashing procedure will permanently erase all data on your Cubot J9. All your photos, apps, and personal files will be lost. A complete backup to a computer or cloud service is essential before proceeding. Using incorrect options in the flash tool can also damage your phone’s IMEI number, so follow the instructions precisely.
Cubot J9: Quick Device Specifications
Please confirm these details match your phone to ensure you are using the correct firmware file.
- Device Name/Model:
- Cubot J9
- Release Date:
- July 2020
- Chipset:
- MediaTek MT6580 (28nm TSMC) with Mali-400 MP2 GPU
- Display:
- 6.2 inches, 720 x 1520 pixels (HD+), IPS LCD with waterdrop notch
- Battery:
- 4200 mAh, Detachable Li-Ion with Type-C fast charging
- RAM/Storage:
- 2GB RAM / 16GB Internal Storage
- Key Features:
- Sony 13MP Main Camera + 2MP Macro + 0.3MP Depth + 0.3MP Portrait (Quadruple Array), 8MP Front Camera with AI Beautification, Face Unlock Security, Type-C USB 2.0 OTG Port, Gradient Color Design
Required Downloads for Flashing
You will need the following tools and drivers to flash your phone successfully.
- SP Flash Tool (Latest Version)
- MediaTek VCOM USB Drivers
- A Cubot J9 Firmware Package (choose a version from the table below)
Cubot J9 Firmware Download Links
| Filename / Version (Build Date) | Android Version | Size | Download Link/s |
|---|---|---|---|
| Cubot_J9_V15 (Oct 2020) | 10 Stock | 795MB | Download (MEGA) |
| Cubot_J9_V13 (Sep 2020) | 10 Stock | 943MB | Download (Google Drive) |
How to Flash Cubot J9 Firmware
This is a summary of the flashing process using SP Flash Tool. For a more comprehensive guide with screenshots, please visit our detailed pillar article.
- Preparation: Download your chosen firmware version, the SP Flash Tool, and MTK VCOM drivers. Extract all zip/rar files into a single, easy-to-access folder.
- Driver Installation: Install the MediaTek VCOM drivers. You may need to disable driver signature enforcement on modern Windows versions.
- Load Firmware: Run
flash_tool.exe. Click the “Scatter-loading File” button and select theMT6580_Android_scatter.txtfile from the extracted firmware folder. - Begin Flashing: Set the dropdown box to “Download Only” to protect your phone’s IMEI. Click the large green “Download” button to put the tool in standby.
- Connect the Phone: Power off your Cubot J9 completely and remove the detachable battery for 10 seconds. Reinsert battery, then press and hold both Volume Up + Volume Down keys simultaneously. While holding the keys, connect the phone to your PC with the Type-C cable. Release the keys once the flashing begins. A green circle will appear when the process is complete.
For in-depth instructions and error solutions for the SP Flash Tool, please visit our complete guide: How to Flash Firmware on MediaTek (MTK) Smartphones.
Troubleshooting Common Issues
Based on extensive user reports from photography communities, GSMArena user reviews, and budget smartphone forums, here are specific problems with the Cubot J9 and their solutions.
1. Quadruple Camera Lens Switching System Complete Failure
Cause: This is the most critical software issue affecting the Sony 13MP + 2MP + 0.3MP + 0.3MP camera array. Users report that the camera app becomes locked on the main 13MP lens and cannot switch to macro, depth, or portrait modes, rendering three of the four lenses unusable. The Mali-400 MP2 GPU struggles with the complex camera switching algorithms.
Solution: The quadruple camera switching requires precise firmware coordination between all four sensors. Clear camera app storage completely: Settings > Apps > Camera > Storage & Cache > Clear Storage. Force-stop all camera-related processes and remove all third-party camera apps that may interfere with lens switching protocols. Flashing the latest firmware (V15) includes updated camera switching algorithms specifically optimized for the Sony quadruple array configuration. Never use portrait mode immediately after firmware flashing as the depth sensors require calibration.
2. Type-C Charging Port Intermittent Connection Failures
Cause: The Type-C implementation on this budget device frequently develops loose connection issues. Users report that the charging cable must be held at specific angles or repeatedly reinserted to maintain charging, indicating mechanical connector wear or software power management conflicts.
Solution: The Type-C port mechanical design is prone to loosening with repeated insertions. Clean the port carefully with compressed air to remove dust and debris. Inspect the charging cable connector for wear or deformation. Try different Type-C cables as the J9’s budget implementation may not support all cable specifications. For software-related charging issues, the detachable battery design allows complete power cycling: remove battery for 60 seconds, reinsert, then test charging. The V15 firmware includes improved Type-C power management that resolves some connection instability.
3. Face Unlock Recognition System Persistent Authentication Failures
Cause: The face unlock system becomes increasingly unreliable after software updates or when using the device in different lighting conditions. Users report “Can’t Verify Face” errors even after re-enrolling facial data multiple times, particularly on gradient-colored variants where the front camera sensor may have calibration issues.
Solution: The 8MP front camera with AI beautification can conflict with face unlock algorithms. Delete all existing facial data: Settings > Security > Face Unlock > Delete facial data. Re-enroll face data in optimal lighting conditions (not direct sunlight or complete darkness) with the camera lens completely clean. Disable any third-party themes that may interfere with the face unlock interface. If recognition continues failing, the gradient color variants may have front camera sensor issues requiring firmware-level calibration adjustments available in V15.
4. Stock Android 10 Severe Performance Degradation
Cause: The MediaTek MT6580 with only 2GB RAM becomes catastrophically overloaded by Stock Android 10’s resource requirements. Users report complete system freezes, app crashes, and inability to multitask even basic applications. The Mali-400 MP2 GPU cannot handle modern Android 10 interface animations.
Solution: The MT6580 chipset was designed for Android 6.0-7.0 maximum performance. Disable all animation settings: Settings > Developer Options > Animation Scale (set all to 0.5x or off). Limit background app refresh and disable automatic app updates. Keep at least 80% of the 16GB storage free as the limited RAM requires heavy swap file usage. Consider using only the most essential applications – the hardware cannot support modern app complexity.
5. Gradient Color Back Panel Coating Deterioration
Cause: The distinctive gradient color finishes in Blue, Black, and Green variants suffer from coating degradation that affects both appearance and functionality. Users report that the gradient coating wears off with normal use, exposing the plastic substrate underneath and potentially affecting internal antenna performance.
Solution: The gradient coating is applied over plastic housing and is not durable for long-term use. Use a protective case immediately to prevent further coating wear. The coating deterioration is purely cosmetic and does not affect core functionality, but may impact resale value. Clean gently with alcohol-free cleaning solutions only as harsh chemicals accelerate coating breakdown. This is a hardware design limitation that firmware updates cannot address.
Frequently Asked Questions (FAQs)
- Why does my quadruple camera system only show one working lens?
- The Sony 13MP + 2MP + 0.3MP + 0.3MP array requires precise software coordination. The MediaTek MT6580 with Mali-400 MP2 GPU struggles with camera switching algorithms. Firmware V15 includes optimized camera switching protocols specifically for this quadruple configuration.
- Is the Type-C charging port issue a hardware or software problem?
- Usually hardware-related due to budget implementation quality. However, firmware V15 includes improved Type-C power management that can resolve some connection instabilities. Clean the port thoroughly before assuming hardware failure.
- Why does face unlock work sometimes but not others?
- The 8MP front camera with AI beautification can conflict with face unlock algorithms. Lighting conditions, gradient color variant calibration differences, and third-party app interference commonly cause recognition failures. Re-enrollment in optimal conditions often resolves issues.
- Can I improve the MT6580 processor performance with firmware updates?
- Limited improvement possible. The MT6580 with 2GB RAM is severely inadequate for Stock Android 10. Firmware V15 includes some optimization, but hardware limitations prevent significant performance gains.
- Will the gradient color coating continue wearing off?
- Yes, this is a design limitation of the coating process over plastic housing. Use protective cases immediately to minimize further deterioration. The coating wear is cosmetic only and doesn’t affect functionality.
- How does the detachable battery affect troubleshooting?
- The detachable 4200mAh battery allows complete power cycling for troubleshooting charging and power management issues. This advantage helps diagnose Type-C charging problems and reset power states.
Conclusion
Restoring the official stock firmware on your Cubot J9 is essential for addressing the complex interplay of issues affecting this budget photography device, particularly the critical quadruple camera lens switching failures, Type-C charging port connection instability, and face unlock recognition system malfunctions. This guide provides all available firmware files and specialized flashing instructions for the MediaTek MT6580-powered Stock Android 10 system.
The innovative Sony quadruple camera array and Type-C implementation make this device unique in the ultra-budget category, but require careful firmware maintenance to function properly. Remember that the gradient color variants and detachable battery design create additional considerations for optimal performance.
If this guide helped you resolve your Cubot J9 issues, please share your experience in the comments, especially which firmware version worked for your specific camera switching or charging port problems and whether the gradient color coating affected your device’s performance. Your feedback helps our community of budget photography enthusiasts dealing with similar quadruple camera system challenges!
