add update script and README changes

README.md

@@ -70,7 +70,10 @@ Hard resetting via RTS pin...
 ```
 
 5. cd into the directory where the release zip file was expanded.
-6. Install the correct firmware for your board with "device-install.sh firmware-_board_-_country_.bin". For instance "./device-install.sh firmware-HELTEC-US-0.0.3.bin".
+6. Install the correct firmware for your board with `device-install.sh firmware-_board_-_country_.bin`. 
+    - Example: `./device-install.sh firmware-HELTEC-US-0.0.3.bin`.
+7. To update run `device-update.sh firmware-_board_-_country_.bin`
+    - Example: `./device-update.sh firmware-HELTEC-US-0.0.3.bin`.
 
 Note: If you have previously installed meshtastic, you don't need to run this full script instead just run "esptool.py --baud 921600 write*flash 0x10000 firmware-\_board*-_country_.bin". This will be faster, also all of your current preferences will be preserved.
 

bin/device-update.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+set -e
+
+FILENAME=$1
+
+echo "Trying to update $FILENAME"
+esptool.py --baud 921600 writeflash 0x10000 $FILENAME