How to update Marsa54/54L firmware.
1. Connect UNPOWERED altimeter to the USB port of your computer. Wait a few moments to allow the computer to recognize the Marsa USB connection.
2. Start the windows MarsaConnect program on the PC, the software should recognize the connected altimeter by a message in the upper right-hand text box. If not close the program and try from 1.
3. Apply power to the altimeter, wait for the display to reach the "Start in 9" etc phase and then push the "Connect" button in MarsaConnect. The display on the altimeter should read "marsa connected". If not then close and unplug everything and try again from step 1.
4. Select the "Download Current Firmware" button in MarsaConnect. Once the firmware is downloaded and verified the "Flash Current Firmware" button will be enabled. Then push that button and the firmware will be downloaded to the altimeter. Do not touch anything while this is going on. When the firmware download is complete the altimeter should restart itself.