Update dfu articles [HC-1230]

content/Hardware Support/Generic/Flash-USB-to-serial-firmware-in-DFU-mode.md → content/Hardware Support/Generic/Flash-USB-to-serial-firmware-in-DFU-Device-Firmware-Update-mode.md

@@ -1,20 +1,20 @@
 ---
-title: "Flash USB-to-serial firmware in DFU mode"
+title: "Flash USB-to-serial firmware in DFU (Device Firmware Update) mode"
 id: 4408887452434
 ---
 
 The following boards use either an Atmega16U2 or Atmega8U2 chip as a USB-to-serial converter:
 
-* Arduino UNO
+* Arduino UNO (Rev1)
 * Arduino UNO Rev3
 * Arduino Mega
 * Arduino Mega2560 Rev3
 * Arduino MegaADK Rev3
 
-The converter chip firmware can be flashed with a computer by setting the board to **DFU mode** (Device Firmware Update).
+The converter chip firmware in these boards can be flashed with a computer by setting the board to **DFU mode** (Device Firmware Update). You may want to use this procedure to restore USB-to-serial functionality if the converter has become corrupted or is not working properly, and resolve communication issues between the board and your computer.
 
 > [!NOTE]
-> This article does _not_ apply to the Uno WiFi Rev2, which uses a different chip with closed source firmware.
+> This article does _not_ apply to the UNO WiFi Rev2, UNO R4 WiFi, and UNO R4 Minima.
 
 ## 1. Get the firmware
 
@@ -27,7 +27,7 @@ Within the platform directory, the usb to serial firmware is found in `firmwares
 | Arduino Mega2560 Rev3 | Arduino-usbserial-atmega16u2-Mega2560-Rev3.hex |
 | Arduino MegaADK Rev3  | Arduino-usbserial-atmega16u2-MegaADK-Rev3.hex  |
 | Arduino UNO Rev3      | Arduino-usbserial-atmega16u2-Uno-Rev3.hex      |
-| Arduino UNO           | Arduino-usbserial-uno.hex                      |
+| Arduino UNO (Rev1)    | Arduino-usbserial-uno.hex                      |
 | Arduino Mega          | Arduino-usbserial-mega.hex                     |
 
 ## 2. Program the chip with the firmware

content/Hardware Support/Generic/If-Arduino-UNO-Rev1-or-Rev3-or-Mega-is-not-recognized-by-the-computer.md

@@ -0,0 +1,13 @@
+---
+title: "If Arduino UNO (Rev1 or Rev3) or Mega is not recognized by the computer"
+id: 4411209176722
+---
+
+Missing or corrupted **USB-to-Serial** firmware can cause UNO (Rev1 and Rev3) and Mega boards to be recognized as any of the following:
+
+- Unknown Device
+- Composite Device
+- ATmega16u2 DFU
+- Atmega8U2 DFU
+
+Resolve the issue by [flashing the USB-to-Serial firmware in DFU (Device Firmware Update) mode](https://support.arduino.cc/hc/en-us/articles/4408887452434).

content/Hardware Support/Generic/Set-a-board-to-DFU-mode.md → content/Hardware Support/Generic/Set-a-UNO-Rev1-and-Rev3-or-Mega-board-to-DFU-Device-Firmware-Update-mode.md

@@ -1,9 +1,9 @@
 ---
-title: "Set a board to DFU mode"
+title: "Set a UNO (Rev1 and Rev3) or Mega board to DFU (Device Firmware Update) mode"
 id: 4410804625682
 ---
 
-UNO (except WiFi Rev2) and Mega boards use either an Atmega16U2 or Atmega8U2 chip as a USB-to-serial converter. By setting a board to **DFU mode** you can [upload USB-to-Serial firmware to the chip](https://support.arduino.cc/hc/en-us/articles/4408887452434-Flash-USB-to-serial-firmware-in-DFU-mode).
+UNO (Rev1 and Rev3), and Mega boards use either an Atmega16U2 or Atmega8U2 chip as a USB-to-serial converter. By setting a board to **DFU mode** (Device Firmware Update) you can [upload USB-to-Serial firmware to the chip](https://support.arduino.cc/hc/en-us/articles/4408887452434-Flash-USB-to-serial-firmware-in-DFU-mode).
 
 1. Connect the board to your computer
 
@@ -17,7 +17,7 @@ The board will reset to DFU mode.
 
 <h2 id="rev1">Short the HWB line (Rev1 models)</h2>
 
-If you're using an Rev1 model, you also need to assert and hold the **HWB line**:
+If you're using a Rev1 model, you also need to assert and hold the **HWB line**:
 
 1. Find the two HWB pads on the back of the board.
 
@@ -35,4 +35,4 @@ The board will reset to DFU mode.
 
 ## Further reading
 
-* [Flash USB-to-Serial firmware in DFU mode](https://support.arduino.cc/hc/en-us/articles/4408887452434-Flash-USB-to-serial-firmware-in-DFU-mode).
+* [Flash USB-to-Serial firmware in Device Firmware Update (DFU) mode](https://support.arduino.cc/hc/en-us/articles/4408887452434-Flash-USB-to-serial-firmware-in-DFU-mode).