Merge pull request #2650 from arduino/canchebagur/nano-r4-user-manual-update-bootloader-2

[PXCT-1474] - Nano R4 Update Tutorial (Bootloader)

Author: canchebagur

content/hardware/03.nano/boards/nano-r4/tutorials/01.user-manual/content.md

@@ -2333,6 +2333,16 @@ The Nano R4's bootloader offers the following technical specifications:
 
 ### Bootloader File Location
 
+The bootloader file (`dfu_nano.hex`) can be obtained in two ways:
+
+**Option 1: Direct Download (recommended)**: 
+
+Download directly from the Arduino GitHub repository:
+
+- [Download dfu_nano.hex](https://github.com/arduino/ArduinoCore-renesas/blob/main/bootloaders/NANOR4/dfu_nano.hex)
+
+**Option 2: From Arduino IDE Installation**:
+
 The bootloader file (`dfu_nano.hex`) is automatically installed with the Arduino UNO R4 Boards core. You can find it in the following locations:
 
 **Windows:**
@@ -2376,8 +2386,7 @@ For detailed step-by-step instructions on recovering and reflashing the bootload
 - Verifying successful bootloader restoration
 - Troubleshooting common issues
 
-***__Important note__: Bootloader recovery is a low-level operation that should only be performed when necessary. __Always ensure you have a stable power supply and follow the tutorial instructions carefully to avoid damaging your board__. If you're unsure whether you need bootloader recovery, try standard troubleshooting steps first or contact [Arduino Support](https://www.arduino.cc/en/contact-us/) for assistance.***
-
+***__Important note__: Bootloader recovery should only be performed when necessary. Ensure stable power supply and follow the tutorial instructions carefully. The process requires only the Renesas Flash Programmer tool and the bootloader file.***
 
 ### Maintaining Bootloader Health
 

content/hardware/03.nano/boards/nano-r4/tutorials/03.bootloader-flashing/assets/bootloader-raw-file.png

@@ -42,11 +42,12 @@ This tutorial will guide you through the complete process of flashing the bootlo
 
 ### Software Requirements
 
-- [Arduino IDE 2.0+](https://www.arduino.cc/en/software/) or [Arduino Web Editor](https://create.arduino.cc/editor)
+- [Arduino IDE](https://www.arduino.cc/en/software/) or [Arduino Cloud Editor](https://create.arduino.cc/editor)
 - [Arduino UNO R4 Boards core](https://github.com/arduino/ArduinoCore-renesas) (latest version)
 - [Renesas Flash Programmer tool](https://www.renesas.com/en/software-tool/renesas-flash-programmer-programming-gui) (latest version)
+- The bootloader file (`dfu_nano.hex`, see next section for download options)
 
-***__Important note__: Make sure you have installed the `Arduino UNO R4 Boards` core version 1.0 or higher before proceeding. The bootloader file is included in this core installation.***
+***__Important note__: The Arduino IDE is NOT required for the bootloader flashing process itself, only for testing the board afterward.***
 
 ## Understanding Bootloader Recovery
 
@@ -60,9 +61,19 @@ The Nano R4 includes a special hardware feature that enables bootloader recovery
 
 ## Preparing for Bootloader Flashing
 
-Before beginning the bootloader flashing process, you need to locate and prepare the necessary bootloader file that comes with the Arduino UNO R4 Boards core installation.
+### Obtaining the Bootloader File
 
-### Locating the Bootloader File
+**Option 1: Direct Download (recommended)**
+
+Download the bootloader file directly from the Arduino Renesas Core GitHub repository:
+
+- [Download dfu_nano.hex](https://github.com/arduino/ArduinoCore-renesas/blob/main/bootloaders/NANOR4/dfu_nano.hex)
+
+Click the "**Download raw file**" button and save it to a known location on your computer, as you will need it later in the Renesas Flash Programmer.
+
+![Bootloader file on the Arduino Renesas Core GitHub repository](assets/bootloader-raw-file.png)
+
+**Option 2: From Arduino IDE Installation (if already installed)**
 
 The bootloader file (`dfu_nano.hex`) is automatically installed when you add the `Arduino UNO R4 Boards` core through the Arduino IDE's Boards Manager. To find this file on your system:
 
@@ -156,9 +167,9 @@ After flashing the bootloader, it is important to verify that your Nano R4 board
 
 **Testing with the Blink Sketch**
 
-Open the Arduino IDE 2 and ensure the Arduino UNO R4 Boards core is installed via **Tools > Board > Boards Manager**. Select your board by navigating to **Tools > Board > Arduino UNO R4 Boards > Arduino Nano R4**. Select the correct port under **Tools > Port**. Your Nano R4 should now appear as "**Arduino Nano R4**".
+Open the Arduino IDE and ensure the **Arduino UNO R4 Boards** core is installed via **Tools > Board > Boards Manager**. Select your board by navigating to **Tools > Board > Arduino UNO R4 Boards > Arduino Nano R4**. Select the correct port under **Tools > Port**. Your Nano R4 should now appear as "**Arduino Nano R4**".
 
-Load the following Blink example sketch to test the bootloader:
+Load the following `Blink` example sketch to test the bootloader:
 
 ```arduino
 /**
@@ -207,6 +218,16 @@ If the upload succeeds and the orange LED starts blinking, your bootloader has b
 
 ![Blink sketch](assets/orange-led.gif)
 
+## Quick Verification
+
+After flashing, your board should:
+
+- ✅ Show up as "**Arduino Nano R4**" in your computer's device manager
+- ✅ Have only the green PWR LED lit when idle
+- ✅ Successfully upload and run the `Blink` sketch (if testing with Arduino IDE)
+
+If any of these checks fail, see the Troubleshooting section below.
+
 ## Troubleshooting Common Issues
 
 If you encounter problems during the bootloader flashing process, here are common issues and solutions: