You can also use the Teensy Loader, which works for Windows,** Linux and Mac**. For Windows, it is available here, for Linux and Mac download "Teensyduino" from here. Load the hex file with "teensy.exe", then launch "teensy_reboot.exe" while the Thermocam is connected to the PC and turned on. The flash procedure should start. In case there is an error "File too big", upload "FileTooBig.hex" to the Teensy first and then the newest version of the firmware in the next step.
In the unlikely case that the update failed and the device does not start any more, load the firmware file again and start the flash procedure, the status should display “Waiting for device...”. Then short the pins P & G on the Teensy for one second with a screwdriver, while the device is turned on and connected to the PC. Afterwards, the flash should start.