While Trueno doesn’t officially support OS X 10.9 and 10.10, it can be made to work with a couple of small tweaks:
Firstly, download the correct installer and follow the installation instructions.
Note: on 10.9 the “Copy Required Data.sh” shell script won’t open with Terminal by default. You can run it by right clicking, selecting open with and then clicking Other… At the bottom of the file menu there should be a dropdown saying Enable: Recommended Applications. Change this to All Applications. Go to Utilities, select Terminal and click open. Enter your password and the script should run normally.
Secondly, once you’ve plugged Trueno into you computer, type the following command into the Terminal:
sudo kextunload -b com.apple.driver.AppleUSBCDCACMData
This will disconnect the kernel extension that is automatically attached in 10.9 and 10.10. This will allow Trueno’s editor to connect to the USB stick. You may need to run the command again if you restart your computer or reconnect the USB stick as the kernel extension may start again.