The new version of Gizmetor and GiziPrint uses some features in the new Marlin. This post will explain how to upgrade the firmware.
Download and unzip the latest Marlin that we use
Download and install Arduino 1.8.5 (https://www.arduino.cc/en/Main/Software)
Open Arduino 1.8.5
Click on File | Preferences
Copy the following into "Additional Boards Manager URLs
Click on Tools | Board | Boards Manager
In the search box, type in "Sanguino"
Click on the line that shows up. It should have the text "Sanguino by Kristian...."
Select version 1.0.2 and install it.
Close the window when done
Click on Tools | Board. Scroll go the bottom and select Sanguino
Click on Tools | Processor | ATmega1284 ... (16 MHz)
Open and upload Marlin
In Arduino 1.8.5 click File | Open
Go to the directory where you unzipped the new Marlin
Open Marlin.ino. It will be between Marlin.h and Marlin_main.cpp.
Click Tools | Port. Select the printer port (If you have multiple ports in the list you will need to click each one and try to upload to it until you have the correct one)
Click on the arrow that points to the right to upload.
If all goes well you will have the newest firmware.