Q1. My fingerprint scanner and Face Unlock are slow and often don't work. Can this be fixed?

This is a very common complaint for the Fast Pro. Flashing the stock firmware can often improve the situation by restoring the original drivers and calibration software for both biometric sensors. After flashing, be sure to delete and re-register your face and fingerprints for best results.

Q2. The main camera on my phone struggles to focus, making pictures blurry. Will this help?

Yes, it can. This is a known software issue with the phone's autofocus algorithm. Reinstalling the official firmware resets the camera software to its factory defaults, which can fix these focusing problems and improve overall camera performance.

Q3. My phone gets very hot, especially when using 4G data. Is this normal?

While some warmth is expected, excessive heat is often made worse by software bugs or background apps. A clean firmware flash ensures the system is running efficiently and can help reduce software-related overheating by closing rogue processes.

BQ Mobile BQ-5515L Fast Pro Firmware (Stock ROM)

The BQ Mobile BQ-5515L Fast Pro is a budget-friendly smartphone from 2018, featuring an 18:9 aspect ratio display and running on Android 8.1 Oreo. It was equipped with modern features for its time, including both a fingerprint scanner and Face Unlock. However, users of the device have frequently reported software-related problems that detract from the experience. The most common complaints include unreliable and slow biometric sensors (both fingerprint and face unlock), camera focus issues resulting in blurry photos, and significant overheating during normal use. For those facing these frustrating issues, flashing the official stock firmware is the most reliable way to restore the device’s software and fix these bugs.

ℹ️ Important Note:
This phone is powered by a MediaTek chipset and requires the SP Flash Tool to install the firmware. This process will completely erase all your personal data. Ensure you have backed up your important files before you begin.

⚠️ Prerequisites: Before You Begin

Click Here for the Essential Pre-Flashing Checklist

Backup Your Data: All your contacts, photos, and files on the phone’s internal storage will be permanently wiped.
Charge The Battery: To prevent the phone from shutting down during the update, ensure the battery is charged to at least 50%.
Windows PC & USB Cable: You will need a Windows computer and a standard micro USB cable to perform the flash.

📱 Quick Device Specifications

Device: BQ Mobile BQ-5515L Fast Pro
Chipset: MediaTek MT6739
Display: 5.5″ HD+ IPS (1440×720)
Operating System: Android 8.1 Oreo
RAM: 2GB
Storage: 16GB
Battery: 2800 mAh

🛠 Required Tools & Downloads

File / Tool	Download Link
SP Flash Tool	Download Tool
MediaTek USB VCOM Drivers	Download Drivers

⬇️ BQ Mobile BQ-5515L Fast Pro Stock ROM / Firmware

Android Version	Build Date	Chipset	Download Link
8.1 Oreo	2018-04-09	MediaTek MT6739	Download (MediaFire)

Quick Steps to Flash BQ-5515L Fast Pro Firmware

Download and install the MediaTek VCOM drivers. Extract the firmware ZIP file (BQ_5515L_..._20180409_8.1.0.zip) and the SP Flash Tool on your PC.
Launch flash_tool.exe. Click the “Scatter-loading” button and select the MT6739_Android_scatter.txt file from the extracted firmware folder.
Ensure the flashing mode in the dropdown menu is set to “Download Only.”
Power off your phone completely. Click the green “Download” button in SP Flash Tool, then immediately connect the powered-off phone to your PC via USB cable.
The flash will start automatically. Once you see the green checkmark pop-up, you can disconnect the phone and power it on.

For a more detailed, step-by-step guide on this process, please refer to our main tutorial:
👉 Full Tutorial: How to Flash MediaTek Firmware with SP Flash Tool

❓ Frequently Asked Questions (FAQs)

Q1. My fingerprint scanner and Face Unlock are slow and often don’t work. Can this be fixed?: This is a very common complaint for the Fast Pro. Flashing the stock firmware can often improve the situation by restoring the original drivers and calibration software for both biometric sensors. After flashing, be sure to delete and re-register your face and fingerprints for best results.
Q2. The main camera on my phone struggles to focus, making pictures blurry. Will this help?: Yes, it can. This is a known software issue with the phone’s autofocus algorithm. Reinstalling the official firmware resets the camera software to its factory defaults, which can fix these focusing problems and improve overall camera performance.
Q3. My phone gets very hot, especially when using 4G data. Is this normal?: While some warmth is expected, excessive heat is often made worse by software bugs or background apps. A clean firmware flash ensures the system is running efficiently and can help reduce software-related overheating by closing rogue processes.

🔧 Device Troubleshooting

I get a “PMT changed for the ROM” error in SP Flash Tool: This error means the partition layout on the phone is different from the one in the firmware file. To fix this, change the flashing mode in SP Flash Tool from “Download Only” to “Firmware Upgrade” and try again.
SP Flash Tool shows a BROM ERROR or the phone is not detected: This is a driver issue. Ensure the MediaTek VCOM drivers are correctly installed (you may need to disable Windows Driver Signature Enforcement). Use a good quality USB cable and a main USB port on your PC. Make sure the phone is completely powered off before connecting it.
The phone is stuck in a bootloop after a successful flash: The first boot can be slow. If it is still stuck after 15 minutes, you need to clear old data. Boot into recovery mode (Power + Volume Up), select “Wipe data/factory reset,” and then reboot.