small dfu clarifications

Author: peter-pycom

content/updatefirmware/expansionboard.md

@@ -29,10 +29,10 @@ In normal operation, the expansionboard is in Application mode. However when we
 
 | Board | DFU bootloader (update mode) | Application firmware (normal mode) |
 | :--- | :--- | :--- |
-| Pygate | `0xED15` | `0xED14` |
-| Pytrack | `0xF014` | `0xF013` |
-| Pysense | `0xF011` | `0xF012` |
-| Pyscan | `0xEF37` | `0xEF38` |
+| Pygate  | `0xED15` | `0xED14` |
+| Pytrack  | `0xF014` | `0xF013` |
+| Pysense  | `0xF011` | `0xF012` |
+| Pyscan  | `0xEF37` | `0xEF38` |
 | Expansion Board v3 | `0xEF99` | `0xEF98` |
 
 _Note: USB Vendor ID is always_ `0x04D8`
@@ -61,8 +61,8 @@ _Note: USB Vendor ID is always_ `0x04D8`
 
  * Windows
 
- Download and install [DFU-util v0.9](http://dfu-util.sourceforge.net/releases/dfu-util-0.9-win64.zip) 
- 
+ Download and install [DFU-util v0.9](http://dfu-util.sourceforge.net/releases/dfu-util-0.9-win64.zip)
+
  For Windows, we will need to install separate drivers for the board to recognized as a Pycom board in DFU mode.
  1. Disconnect the USB cable to your expansion board
  2. Hold down the DFU mode button on the shield
@@ -92,7 +92,7 @@ To enter update mode follow these steps:
 1. Navigate the terminal to the folder where you downloaded the `.dfu` file to
 2. Unplug the device
 3. Remove the development module
-4. Press this button on your device:
+4. Press and hold the S1/MCLR button on your device. Highlighted in red below:
 
 | Expansionboard 3.1 | Pygate | Pysense | Pysense 2.0 X | Pytrack | Pytrack 2.0 X | PyScan |
 |:----|:----|:-----|:--------|:-----|:-----|:----|
@@ -145,9 +145,9 @@ Done!
 
 Using `lsusb` command, the device should be visible in both normal and bootloader modes.
 
-For exemple, a Pytrack board is visible as either:
+For example, a Pytrack board is visible as either:
 
 * `Bus 020 Device 004: ID 04d8:f014 Microchip Technology Inc. Application Specific Device`
- * this is bootloader mode (`f014` is USB PID), active just for 7-8 seconds, if the reset button was just pressed before plugging USB connector.
+ * This is the bootloader mode (`f014` is USB PID). It is active for just 7-8 seconds, if the MCLR button was pressed just before plugging in the USB connector.
 * `Bus 020 Device 005: ID 04d8:f013 Microchip Technology Inc. Pytrack Serial: Pyabcde0`
- * this is normal, application mode (`f013` is USB PID), this means the bootloader verified application partition and it boot-up correctly.
+ * This is the normal, application mode (`f013` is USB PID). This means the bootloader verified the firmware and it boot-up correctly.