Fix Lenovo A850 Flash Fail: A Comprehensive Guide to Using SP Flash Tool

Experiencing issues while flashing your Lenovo A850? Encountering the dreaded “Tool DL Image Fail” error? You’re not alone. Many Lenovo A850 users face this problem when attempting to update or restore their device’s firmware. This guide will walk you through the process of flashing your Lenovo A850 using SP Flash Tool and, more importantly, how to troubleshoot and overcome the “Tool DL Image Fail” error.

Whether your Lenovo A850 is stuck in a bootloop, unresponsive after a failed update, or you simply want to refresh your device with a clean stock ROM, flashing is often the solution. This tutorial is designed to be comprehensive and user-friendly, ensuring you can successfully revive your Lenovo A850.

Before we begin, it’s crucial to understand why you might encounter the “Tool DL Image Fail” error. This error typically arises due to issues with the Download Agent (DA) file, scatter file, or compatibility problems between the SP Flash Tool version, ROM, and your device. Incorrect driver installation or USB connectivity problems can also contribute to flashing failures.

This guide aims to address these potential pitfalls and provide you with a step-by-step solution to flash your Lenovo A850 successfully, even if you’re facing the “Tool DL Image Fail” error. Let’s get started.

Requirements:

To flash your Lenovo A850, you will need the following:

Lenovo A850 Stock ROM: Download the correct stock ROM for your Lenovo A850 model. Ensure it is compatible with your device variant.
SP Flash Tool: Download the latest version of SP Flash Tool. It’s recommended to use a version known to be stable with MediaTek devices.
USB VCOM Drivers: These drivers are essential for your computer to recognize your Lenovo A850 in Preloader mode. You can download them from a reliable source, ensuring compatibility with your operating system.

USB VCOM Driver

Once you have downloaded all the necessary files, proceed with the following steps. It’s advisable to ensure your phone has at least 30-60% battery charge before starting the flashing process to prevent interruptions.

Step 1: Extracting Files

Begin by extracting all the downloaded ZIP files. Create separate folders for each to keep things organized – one for the Stock ROM, one for SP Flash Tool, and one for the USB VCOM drivers.

Step 2: Installing USB VCOM Drivers

This is a critical step. Incorrect or outdated drivers are a common cause of flashing errors, including “Tool DL Image Fail.”

Open Device Manager on your computer. (You can find it by searching “Device Manager” in the Start Menu).
Power off your Lenovo A850 and remove the battery. (If your device has a non-removable battery, power it off completely).
Connect your Lenovo A850 to your computer via a USB cable. Use a high-quality USB cable and a direct USB port on your computer (avoid USB hubs if possible).
As soon as you connect your phone, watch for a new device appearing in Device Manager, usually under “Ports (COM & LPT)” or “Other devices” as “Mediatek Preloader USB VCOM Port” or a similar name. It might appear and disappear quickly.

If the device appears and disappears rapidly, you need to be quick to update the driver.
Right-click on the Mediatek Preloader device and select “Update driver.”
Choose “Browse my computer for drivers.”
Click “Browse…” and navigate to the folder where you extracted the USB VCOM drivers.
Make sure “Include subfolders” is checked and click “Next.”
If you see a security prompt, click “Install this driver software anyway.”
Once the driver installation is complete, you should see “Mediatek Preloader USB VCOM Port” listed under “Ports (COM & LPT)” in Device Manager without any exclamation marks or errors.

Step 3: Flashing the Stock ROM using SP Flash Tool

Now that the drivers are correctly installed, you can proceed with flashing the Stock ROM onto your Lenovo A850.

Disconnect your phone from the computer and reinsert the battery. (If you removed it). Do not power on the device.
Open the SP Flash Tool folder and run flash_tool.exe.
In SP Flash Tool, go to Options > Options > Download. Check the box next to “DA DL All with checksum.” This can help prevent “Tool DL Image Fail” errors caused by checksum mismatches.
Click on “Scatter-loading File” and navigate to the Stock ROM folder you extracted earlier. Select the MTxxxx_Android_scatter.txt file (xxxx will vary depending on your MediaTek chipset).
From the dropdown menu, ensure that “Download Only” is selected. Initially, try with “Download Only”. If you encounter errors, especially if you suspect partition issues, you might need to use “Firmware Upgrade” – but be cautious with this option as it can potentially cause more issues if not used correctly.
Click the “Download” button (the green arrow). SP Flash Tool will now wait for your device to connect.
Connect your powered-off Lenovo A850 to your computer via USB cable. The flashing process should begin automatically. You will see a progress bar in SP Flash Tool indicating the status.
Wait patiently for the flashing process to complete. Do not interrupt the process or disconnect your device.
Once the flashing is successful, you will see a “Download OK” pop-up with a green checkmark.
Disconnect your Lenovo A850 from the computer and power it on. The first boot after flashing may take longer than usual, so be patient.

Troubleshooting “Tool DL Image Fail” and Other Errors

If you encountered the “Tool DL Image Fail” error or any other issues during the flashing process, here are some troubleshooting steps:

Check DA and Scatter Files: Ensure that the Download Agent (DA) and scatter files are compatible with your Lenovo A850 and the SP Flash Tool version you are using. Sometimes, using a different DA file or SP Flash Tool version can resolve compatibility issues. The DA file is usually located within the SP Flash Tool directory.
DA DL All with Checksum: As mentioned earlier, ensure “DA DL All with checksum” is checked in SP Flash Tool Options.
Driver Issues: Double-check your USB VCOM driver installation. Uninstall and reinstall the drivers, ensuring you follow Step 2 precisely. Try different USB ports on your computer.
ROM Compatibility: Verify that the Stock ROM you downloaded is specifically for Lenovo A850 and compatible with your device variant. Using an incorrect ROM can lead to various errors, including “Tool DL Image Fail.”
SP Flash Tool Version: Experiment with different versions of SP Flash Tool. Older or newer versions might work better for your specific device and ROM combination.
Firmware Upgrade Mode (Use with Caution): If “Download Only” fails, and you are confident about your ROM and scatter file, you can try using “Firmware Upgrade” mode in SP Flash Tool. However, be aware that this option can potentially format more partitions and should be used cautiously. Only use “Firmware Upgrade” if you are sure about what you are doing and after trying “Download Only” multiple times.
USB Cable and Port: Use a good quality USB cable and try different USB ports on your computer, preferably USB 2.0 ports if available. Avoid using USB hubs.
Battery Removal (For Persistent Errors): If you are still facing errors, especially if the process gets stuck repeatedly, try flashing without the battery. Remove the battery, connect the device via USB, and then click “Download” in SP Flash Tool. SP Flash Tool might be able to power the device sufficiently for flashing in some cases.

Conclusion

Flashing your Lenovo A850 can seem daunting, especially when encountering errors like “Tool DL Image Fail.” However, by following this comprehensive guide, ensuring correct driver installation, using the appropriate ROM and SP Flash Tool settings, and troubleshooting effectively, you can successfully revive your device.

Remember to be patient and methodical throughout the process. Double-checking each step and trying different troubleshooting methods will increase your chances of success. With persistence, you can overcome the “Tool DL Image Fail” error and restore your Lenovo A850 to its former glory.

If you continue to face issues, consider seeking assistance from online communities and forums dedicated to Lenovo A850 or Android flashing, where experienced users and experts might provide further guidance tailored to your specific situation.