I have been working on a project to wirelessly control the throttle blade angle of an engine over the past year. I am currently on my 3rd revision of the board. The only changes from the 2nd to 3rd revision are a power indicating LED (works) and an intermediate LDO reg. The power control system works as I have tested it with a 9v and the LED lights up and the 5v rail is 5v. Onto the problem, I have been using Nick Gammon's bootloader program and it has worked flawless for me up until now. Since the last revision two things have changed on my laptop. I updated both OsX to Yosemite and Arduino to 1.6.2. I initially tried burning bootloaders onto 3 of my 6 boards with version 1.27. It would seem to freeze after setting the clock divide and attempting to enter programming (just pause here with the TX light constantly lit). Scared that I bricked 3 of my 6 new boards was thinking man this sucks. I tried working with the supposedly ruined 3 today. I tried talking to them again. I was able to try and verify the chips and would successfully complete the task (with a bunch of errors of course). Then I compiled program version 1.27 again this time from my win7 laptop got one of the supposedly bricked chips to connect. I figured ill try to program it. It worked as expected. From that point I was able to use my FTDI and upload code to the board with no problems. I figured I could go and reprogram the rest of the boards so I grabbed one of the new untouched boards and tried it. It connected fine but froze again during programming. I tried updating to version 1.33 (most current) with no avail. I have also tried arduino version 1.0.5 and 1.6.2. I am not really sure where to go from here or what to try. If you have any ideas or would like some more details feel free to comment or ask!
Thanks for reading!