To upload a .hex file to an Arduino board, you can bypass the Arduino IDE and use tools like AVRDUDE (used internally by the IDE) or command-line uploaders. Here's how to do it:

Step-by-Step: Upload .hex File to Arduino
You’ll Need:

• Arduino board (e.g., Uno, Nano, Mega)
• .hex file (compiled sketch or firmware)
• AVRDUDE installed (comes with Arduino IDE or install separately)
• COM port of the Arduino
• Correct board type and upload settings

Option 1: Using AVRDUDE (Command Line)
Command Syntax:

bash

avrdude -C <path_to_avrdude.conf> -v -patmega328p -carduino -P<COMx> -b115200 -D -Uflash:w:<filename.hex>:i

Example for Arduino Uno (Windows):

bash

avrdude -C "C:\Program Files (x86)\Arduino\hardware\tools\avr\etc\avrdude.conf" ^
-patmega328p -carduino -P COM4 -b115200 -D -Uflash:w:"myprogram.hex":i

Example for Linux/macOS:

bash

avrdude -C /etc/avrdude.conf -v -patmega328p -carduino -P /dev/ttyUSB0 -b115200 -D -Uflash:w:myprogram.hex:i

Explanation of Key Parameters:

Important Notes:

• Make sure no other program (like Arduino IDE) is using the COM port.
• Press the Reset button just before uploading if needed (on older boards).
• If you’re unsure of the COM port, check Device Manager (Windows) or ls /dev/tty* on Linux/macOS.

Option 2: Using XLoader (for Windows)
If you're on Windows and want a GUI tool:

1. Download XLoader: https://xloader.russemotto.com/
2. Select:

• .hex file
• Device type (e.g., Arduino Uno, Mega)
• COM port
• Baud rate

3. Click Upload

Option 3: Arduino IDE with Sketch Precompiled
If you have the .hex but still want to use the Arduino IDE:

• Use an external programmer (e.g., USBasp)
• Or use Sketch > Export compiled Binary, then upload it via tools