This article provides the official download link and installation instructions for the BQ Aquaris M5.5 stock ROM (firmware), version 2.2.1. If your Aquaris M5.5 has become slow, is stuck on the BQ logo, or is suffering from persistent software bugs, reinstalling the official firmware is the most comprehensive solution. This package contains the original BQ software for the device, which is powered by the Qualcomm Snapdragon 615 chipset. Flashing the stock ROM is the best way to unbrick a BQ Aquaris M5.5, remove viruses, and resolve issues that a simple factory reset cannot fix, restoring the phone to its factory condition.
The BQ Aquaris M5.5 was a popular mid-range phablet known for its large Full HD display and solid battery life. Restoring its software will bring back that stable and reliable performance. This firmware package is installed using a fastboot script (`flash-all.bat`), which automatically flashes all necessary partitions to the device.
User Data Advisory for the BQ Aquaris M5.5
Critical Data Warning: Proceeding with this fastboot flashing method will unlock the bootloader and completely erase all personal data on your BQ Aquaris M5.5. This includes your contacts, photos, videos, messages, and installed applications. A full backup to a computer or cloud service is mandatory before you begin this process.
BQ Aquaris M5.5: Quick Device Specifications
Please check your device’s specifications to ensure you are downloading the correct files. This firmware is only for the BQ Aquaris M5.5.
- Device Model:
- BQ Aquaris M5.5
- Release Date:
- 2015
- Chipset:
- Qualcomm MSM8939 Snapdragon 615 (28 nm)
- Display:
- 5.5 inches, 1080 x 1920 pixels (Full HD)
- Battery:
- 3620 mAh, Non-removable Li-Po
- RAM/Storage:
- 2GB/16GB, 3GB/16GB, 3GB/32GB
- Original OS:
- Android 5.1.1 (Lollipop)
Required Downloads for Flashing
To perform the update, you will need the following software and drivers on your computer.
- Android SDK Platform-Tools (for latest ADB and Fastboot drivers)
- Qualcomm QDLoader HS-USB Drivers
- The BQ Aquaris M5.5 Firmware Package (linked in the table below)
BQ Aquaris M5.5 Firmware Download Links
| Filename | Android Version | Size | Download Link/s |
|---|---|---|---|
| BQ_Aquaris_M5.5_2.2.1_20160920.zip | Based on Android 5.1.1 Lollipop | 998MB | Download (MediaFire) |
How to Flash BQ Aquaris M5.5 Stock Firmware (Fastboot Method)
This firmware is installed using a batch script that automates the fastboot flashing process. Follow these steps precisely.
- Preparation: Install the Qualcomm drivers. Download and extract the BQ Aquaris M5.5 firmware zip file to a simple path on your computer (e.g.,
C:\BQ). - Enable OEM Unlocking: On your phone, go to Settings > About phone and tap “Build number” 7 times. Return to Settings, go to Developer options, and enable “OEM unlocking” and “USB debugging”.
- Boot into Fastboot Mode: Power off your phone completely. Then, press and hold the Volume Down + Power buttons together until you see the fastboot/bootloader screen.
- Unlock the Bootloader: Connect your phone to the PC. Open a command prompt, navigate to your platform-tools folder, and type
fastboot oem unlock-go. This will wipe your device data. Your phone will reboot. Power it off and re-enter fastboot mode. - Run the Flashing Script: With the phone connected in fastboot mode, navigate to the folder where you extracted the firmware. Find the file named
flash-all.batand double-click it to run. - Completion: A command window will open and automatically flash all the required partitions. Do not disconnect the phone. The device will reboot automatically into the newly installed OS upon completion.
Troubleshooting Common Issues
Here are solutions to potential problems when using the fastboot flashing method.
1. Command Window shows “waiting for device”
Cause: This means your computer does not detect the phone in fastboot mode. It’s almost always a driver issue.
Solution: Open Device Manager on your PC while the phone is connected in fastboot mode. Look for a device listed as “Android” or “Unknown Device” with a yellow triangle. Right-click it, select “Update Driver,” choose “Browse my computer,” and point it to the Qualcomm/Platform-Tools driver folder. You can also try a different USB port (preferably a USB 2.0 port on the back of the computer) and a different USB cable.
2. The `flash-all.bat` script opens and closes immediately
Cause: This could be due to a corrupted download or an issue with the fastboot executable included in the firmware package. It can also happen if the file path contains spaces or special characters.
Solution: First, re-download and re-extract the firmware file to a simple path like C:\BQ_M5.5. If it still fails, copy the `fastboot.exe` from the latest Android SDK Platform-Tools you downloaded and paste it into the firmware folder, overwriting the existing one. Then, try running the script again.
3. Overheating During Normal Use
Cause: The first-generation octa-core Snapdragon 615 chipset was known for running warm, especially during intensive tasks. This can be made worse by rogue apps or software bugs consuming CPU cycles in the background.
Solution: Installing a clean stock firmware removes any software-related causes of overheating. After installation, be selective about the apps you reinstall. Avoid running graphically demanding games for extended periods. If the phone still gets excessively hot with light use (e.g., browsing), it may indicate an aging battery or hardware issue.
Frequently Asked Questions (FAQs)
- What is the difference between this Fastboot method and ADB Sideload?
- ADB Sideload installs a single update package (`.zip`) from within the phone’s recovery mode. The Fastboot method described here is more powerful; it communicates with the phone’s bootloader to flash individual partition images (`.img` files like boot, system, recovery, etc.) directly from a computer. The `flash-all.bat` script simply automates this process.
- My phone is asking for a Google account after flashing. What do I do?
- This is Factory Reset Protection (FRP). You must log in with the same Google account that was previously synced to the device before the flash. If you don’t have access to that account, you will need to search for a specific FRP bypass method for the BQ Aquaris M5.5.
- Will this firmware fix an “Invalid IMEI” or “No Service” issue?
- This is unlikely. IMEI and baseband information are stored in a separate partition (EFS/NVRAM) that is not typically overwritten by this flashing script. If your IMEI is lost, you may need to use specialized Qualcomm tools to restore it from a backup.
- Is unlocking the bootloader on my BQ Aquaris M5.5 permanent?
- Yes, once you unlock the bootloader, it will remain unlocked unless you specifically re-lock it using a fastboot command (
fastboot oem lock). For normal use, it is perfectly safe to leave it unlocked.
Conclusion
Restoring your BQ Aquaris M5.5 with the official stock firmware using the fastboot method is the most reliable way to solve critical software problems and restore the phone to its original state. This guide provides the official files and a corrected, accurate method for the installation. Always remember to back up your personal data before starting the process.
If this guide helped you revive your phone, or if you have any questions, please let us know in the comments section below. Bookmark our site for more helpful guides and firmware downloads.
