Teensy

The Teensy Loader is a macOS application for flashing firmware onto Teensy development boards. It can be launched directly from a disk image or copied to the hard drive, and it integrates with the Arduino IDE, automatically starting when Verify or Upload is selected. The tool recognizes a connected Teensy, displays the selected HEX file and memory usage, and provides Program, Reboot, and Automatic Mode operations via menus or toolbar buttons.

Users can load HEX files by opening them through the file dialog, toolbar button, or drag‑and‑drop onto the window. In Automatic Mode, the Loader continuously monitors the board; pressing the Teensy’s pushbutton triggers an immediate flash and reboot using the most recent HEX file, streamlining iterative development cycles.

The utility supports Teensy 3.0 when installed via Teensyduino and runs on macOS 10.10 and later, offering a simple graphical interface for rapid firmware deployment without requiring command‑line tools.