This commandline application for the Micronucleus bootloader is written by ihsan Kehribar and Bluebie It's been tested casually on Mac, Windows, and Linux, and aught to work on all three. To make and install, do the regular 'make; sudo make install' on unixes. On windows just 'make' with mingw and do whatever people do with windows exes. Usage on Ubuntu: sudo micronucleus --run name_of_the_file.hex Usage on Mac: micronucleus --run name_of_the_file.hex Usage on Windows micronucleus.exe --run name_of_the_file.hex Raw binary file writing hasn't been tested as much as hex files. Every now and then the program fails once it reaches the Writing stage - this is a known bug - but if you simply rerun the micronucleus command immediately, it will succeed the second time usually. Most of the time this issue is not present. To linux users: sudo is used above because the default configuration under most modern linux distributions is to not allow userspace apps to communicate directly to unknown USB devices. You can fix this by installing some config files, or you can just use sudo. Either way you're going to need root. To configure your system to allow micronucleus access from non-root users, copy 49-micronucleus.rules from this folder to /etc/udev/rules.d/