How to Fix 'Please Use Custom EMI/Preloader to Boot' Error Using Unlock Tool

If you're facing the 'Please use custom EMI/Preloader to boot, Please select correct preloader or from firmware' error on your Android device, you're not alone. This error can be frustrating, but with the right steps, you can resolve it using the Unlock Tool. In this guide, we'll walk you through the entire process, explain why your phone might not connect with the tool, provide troubleshooting tips, and highlight the minimum battery requirements for a successful unlock.

What Causes the 'Custom EMI/Preloader' Error?

This error typically occurs when your device's preloader is incompatible with the current firmware or is corrupted. It prevents your phone from booting properly, causing it to get stuck in a boot loop or fail to start altogether.

Step-by-Step Guide to Fix the 'Custom EMI/Preloader' Error Using Unlock Tool

Step 1: Open Unlock Tool

Start by opening the Unlock Tool on your computer. You'll need to enter your username and password, as this tool is not available for free.

Step 2: Navigate to the MediaTek Tab

Once you're logged in, navigate to the "MediaTek" tab within the tool.

Step 3: Select Custom Preloader/EMI

Click on "Custom Preloader | EMI." This option allows you to choose the appropriate preloader for your specific device.

Step 4: Choose the Correct Preloader

Select the preloader according to your device. For example, if you're working with a Redmi 9 (cattail) running the 12.0.8.0 Global firmware, you'll choose the corresponding preloader from the list.

Step 5: Erase FRP

After selecting the preloader, click on the "ERASE FRP" option to proceed.

Step 6: Connect Your Phone

To connect your phone to the Unlock Tool, press and hold the Volume Up button, then insert the USB cable into your phone. Ensure that the MediaTek USB Driver is installed on your computer. Without the correct drivers, your device will not connect. If you don't have the drivers installed, download them and install them before rebooting your computer and trying again.

Step 7: Wait for the Process to Complete

The Unlock Tool will now work to fix the issue. Wait until the process is completed before disconnecting your device.

Reasons Why Your Android Phone Might Not Connect to the Tool

1. Missing or Incorrect USB Drivers: The most common reason is that the necessary USB drivers are not installed, or they are not the correct ones for your device.
2. Faulty USB Cable or Port: A damaged USB cable or malfunctioning USB port can prevent the phone from connecting properly.
3. Battery Level: If your phone’s battery is too low, it may not connect to the tool. Ensure your device has at least 50% battery before starting the process.

Troubleshooting Connection Issues

• Check USB Drivers: Make sure the MediaTek USB drivers are correctly installed. If they are outdated, update them.

• Try a Different USB Port or Cable: Sometimes switching the USB port or using a different cable can resolve connection issues.

• Restart Both Devices: Reboot both your phone and computer to clear any temporary issues.

• Disable Antivirus Software: Some antivirus programs can interfere with the connection. Temporarily disable them if you encounter problems.

Minimum Battery Requirements for Using Unlock Tool

Before starting the unlocking process, ensure your device has a minimum of 50% battery. This ensures the phone won't power off during the procedure, which could lead to further complications.

Conclusion

Fixing the 'Please use custom EMI/Preloader to boot' error doesn't have to be a daunting task. With the steps outlined above and a little patience, you can successfully resolve this issue using the Unlock Tool. If your phone isn't connecting, remember to check your USB drivers, try different cables, and ensure your battery is adequately charged. With these tips, you'll have your device up and running in no time!

For more guides and troubleshooting tips, be sure to check out our other articles.