This page provides the official download link for the BQ Aquaris M4.5 stock ROM, software version 1.2.0, based on Android 5.1 Lollipop. The Aquaris M4.5 was a compact 4G smartphone released in 2015, appealing to users who preferred smaller, easy-to-handle devices. If your Aquaris M4.5 is stuck in a bootloop, has been bricked by a failed update, or is suffering from critical software issues like a null or “Invalid IMEI,” reinstalling the official firmware is the most powerful solution. This package is specifically for the MediaTek MT6735M chipset variant.
Using the SP Flash Tool, this firmware will allow you to perform a clean installation of the original operating system. This is the definitive method to unbrick a BQ Aquaris M4.5 and resolve deep-seated software errors that a factory reset cannot fix. Please follow the instructions and warnings carefully.
User Data Advisory for the BQ Aquaris M4.5
Critical Flashing Notice: The process described below will completely erase all personal data from your BQ Aquaris M4.5, including photos, contacts, and apps. A full backup is mandatory. Furthermore, using incorrect options in the flash tool can permanently erase your phone’s IMEI number, preventing network access. Proceed with caution and follow the instructions precisely.
BQ Aquaris M4.5: Quick Device Specifications
Please verify these specifications to ensure you are using the correct firmware for your device.
- Device Model:
- BQ Aquaris M4.5
- Release Date:
- June 2015
- Chipset:
- MediaTek MT6735M (Quad-core 1.0 GHz Cortex-A53)
- Display:
- 4.5 inches, 540 x 960 pixels (qHD)
- Battery:
- 2470 mAh, Non-removable Li-Po
- RAM/Storage:
- 1GB/8GB, 1GB/16GB, 2GB/16GB
- Key Features:
- Compact design, 4G LTE, Dual SIM
Required Downloads for Flashing
You will need the following tools and drivers to flash the firmware onto your device.
- SP Flash Tool (Latest Version)
- MediaTek VCOM USB Drivers
- The BQ Aquaris M4.5 Firmware Package (from the table below)
BQ Aquaris M4.5 Firmware Download Links
| Filename | Android Version | Size | Download Link/s |
|---|---|---|---|
| BQ_Aquaris_M4.5_5.1_1.2.0_20150907.zip | 5.1 Lollipop | 771MB | Download (MediaFire) |
How to Flash BQ Aquaris M4.5 Firmware
This is a summary of the flashing process using SP Flash Tool. For a more comprehensive guide, please visit our detailed pillar article.
- Preparation: Download and extract the firmware, SP Flash Tool, and MTK VCOM drivers to a folder on your PC.
- Driver Installation: Install the MediaTek VCOM drivers. You may need to disable driver signature enforcement on Windows for the drivers to install correctly.
- Load Firmware: Launch
flash_tool.exe. Click on the “Scatter-loading File” button, navigate to the extracted firmware folder, and select theMT6735M_Android_scatter.txtfile. - Begin Flashing: Crucially, ensure the dropdown box is set to “Download Only”. Never use the “Format All + Download” option as it will erase your IMEI. Click the large green “Download” button.
- Connect the Phone: Power off your BQ Aquaris M4.5 completely. Connect it to the computer with a good quality USB cable. The flashing process will begin automatically, and a green tick will appear when it 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
Here are some specific issues you might encounter with the BQ Aquaris M4.5.
1. “Invalid IMEI” or No SIM Card Detected After Flashing
Cause: This is a serious issue common to MediaTek devices. It occurs when the NVRAM partition, which stores your phone’s unique IMEI numbers, is corrupted or erased. This is almost always caused by using the “Format All + Download” option in SP Flash Tool.
Solution: Always flash using “Download Only” mode. If your IMEI is already gone, this firmware flash will not restore it. Restoring a lost IMEI is a complex process requiring specialized tools like Maui META and your phone’s original IMEI number (found on the box or device sticker).
2. Phone is Dead and Won’t Turn On (Hard Brick)
Cause: A failed update or incorrect file flash can sometimes leave the device completely unresponsive.
Solution: SP Flash Tool is excellent at recovering from this state. As long as your PC can detect the phone’s MTK Preloader port when you plug it in (you might hear a connection sound), the tool can force-flash the stock firmware and bring the device back to life. This is a key advantage of MediaTek chipsets.
3. GPS is Very Slow to Get a Location Lock
Cause: Budget MediaTek chipsets of this era were not known for fast GPS performance. This can be worsened by corrupted A-GPS (Assisted GPS) data.
Solution: Flashing the stock ROM resets the GPS configuration. After the first boot, enable Wi-Fi and Location services and stand outdoors with a clear sky view for 5-10 minutes to help the GPS perform a “cold start” and download fresh satellite data. This can significantly improve lock-on times.
Frequently Asked Questions (FAQs)
- Will this firmware update my Aquaris M4.5 to Android 6.0 (Marshmallow)?
- No. This is an official Android 5.1 Lollipop firmware package. While an official Marshmallow update was released for the BQ Aquaris M4.5, you would need to find that specific newer firmware file to upgrade.
- My SIM card is not detected after flashing. What happened?
- This is a symptom of having a lost or “invalid” IMEI number. The phone’s modem cannot register on a cellular network without a valid IMEI. Refer to the “Invalid IMEI” troubleshooting point above. You must restore your IMEI to fix this.
- Why is my phone still slow after flashing the firmware?
- While flashing provides a clean, optimized system, the BQ Aquaris M4.5 has modest hardware (1.0 GHz CPU and 1GB RAM on some models). Modern apps can be demanding. For the best performance, use “Lite” versions of apps (like Facebook Lite) and avoid running many applications at once.
- What does a “BROM ERROR” in SP Flash Tool mean?
- This is a general communication error. It usually means the VCOM drivers are not installed correctly, you are using a bad USB cable or port, or you tried to connect the phone before clicking the “Download” button. Reinstall drivers, change the cable/port, and follow the flashing sequence exactly.
Conclusion
Restoring the official Android 5.1 firmware on your BQ Aquaris M4.5 is the most effective way to solve critical software problems, from a completely dead device to persistent network errors. This guide provides the authentic firmware and a safe flashing method to get your compact smartphone running properly again. Pay close attention to the warnings to protect your device’s IMEI number.
If this guide helped you revive your phone, please let us know in the comments. Your feedback is valuable!
