Fixing the Nano Duo Screen Stuck on the LONGER Logo

If your Nano Duo screen is stuck on the LONGER logo during startup, the issue is usually related to corrupted or incomplete firmware. Fortunately, the problem can typically be resolved by reflashing the firmware using the official recovery method.

This guide explains the complete process step by step in a beginner-friendly format while preserving the original flashing procedure and settings exactly as required.

Table of Contents

1. What This Guide Covers
2. Quick Answer
3. Why This Process Matters
4. Before You Start
   • Requirements
   • Precautions
5. Step-by-Step Tutorial
6. Common Problems and Solutions
7. Tips for Better Results
8. Frequently Asked Questions
9. Final Thoughts

What This Guide Covers

This tutorial explains how to recover a Nano Duo machine when the display freezes on the LONGER startup logo.

You will learn:

• How to prepare the firmware flashing tool
• Which firmware file to use
• How to configure the correct flashing parameters
• How to erase and reflash the firmware safely
• What to do if the process does not complete successfully

The instructions below preserve the original operation sequence and parameter values exactly.

Quick Answer

If the Nano Duo screen stays stuck on the LONGER logo during startup, reflash the firmware using flash_download_tool_3.9.5.exe, select ESP32-S3, load firmware_grbl.bin, set the firmware address to 0x0, choose the correct COM port, set BAUD: 912600, then click ERASE followed by START. After the process displays FINISH, restart the machine.

Why This Process Matters

Firmware controls the startup and operation of the Nano Duo. If the firmware becomes damaged, incomplete, or corrupted, the machine may fail to boot normally and remain frozen on the LONGER logo screen.

Reflashing the firmware restores the machine’s core system files and allows the Nano Duo to start correctly again. Following the official flashing sequence carefully helps avoid additional startup issues or failed firmware recovery attempts.

Before You Start

Requirements

Before beginning, prepare the following items:

• Nano Duo machine
• Windows computer
• USB cable compatible with the machine
• flash_download_tool_3.9.5.exe
• firmware_grbl.bin firmware file

Follow official machine specifications or instructions if additional drivers or accessories are required.

Precautions

Before performing firmware recovery, keep these important safety notes in mind:

• Do not disconnect the USB cable during flashing.
• Do not power off the machine while firmware is being written.
• Make sure the correct COM port is selected.
• Double-check all parameters before clicking START.
• Close unnecessary software to reduce communication interruptions.
• Use a stable power source during the process.

Incorrect flashing parameters or interrupting the process may prevent the machine from booting properly.

Step-by-Step Tutorial

Step 1: Prepare Tools

Action

Use the flash_download_tool_3.9.5.exe tool.

Expected Result

The firmware flashing tool is available and ready to launch on your computer.

Important Notes

Ensure the tool is fully downloaded before opening it. Running incomplete or corrupted files may cause flashing errors.

Step 2: Preparing Firmware

Action

Prepare the firmware file:

firmware_grbl.bin

Expected Result

The firmware file is ready to be selected inside the flashing tool.

Important Notes

Do not rename the firmware file. Keep it in an easy-to-find folder on your computer.

Step 3: Open the Flash Tool

Action

Open the flash_download_tool_3.9.5.exe tool, select ESP32-S3, and click OK.

Expected Result

The tool enters the main flashing interface homepage.

Important Notes

Selecting the correct chip type is critical. Ensure ESP32-S3 is selected exactly as specified.

Step 4: Configure Firmware and Flash the Machine

Action

After entering the homepage:

1. Click the three dots in the middle.
2. Find the prepared firmware and open it.
3. Change the firmware to: 0x0
4. Select the COM port corresponding to the machine's port number.
5. Select BAUD: 912600
6. Click ERASE and wait for the status to complete.
7. Click START and wait for the status to display FINISH.
8. Power off and restart the machine.

Expected Result

The firmware flashing completes successfully, and the machine restarts normally instead of remaining stuck on the LONGER logo.

Important Notes

• Wait patiently during both the ERASE and START processes.
• Do not disconnect cables or close the software during flashing.
• The process may take several minutes depending on the computer and connection stability.
• If the status does not display FINISH, repeat the procedure carefully.

Conclusion

That’s the complete procedure for resolving the issue where the Nano Duo screen is stuck displaying the LONGER logo. The success of this process mainly depends on accurate parameter configuration and following the flashing steps in the correct order. As long as each setting is verified carefully and the sequence is strictly followed, the firmware recovery can be completed smoothly and safely.