I have a few small designs layout out using the Atmega32u4 microprocessor that have the Leonardo bootloader installed using the USBtinyISP and the Arduino 1.0.3 IDE. I just choose the Leonardo and the board, USBtinyISP and clicked burn bootloader. The board usually runs the code fine on power up but occasionally will not. Every now and then I have to put in a new bootloader for it to work properly again. This has happened on two different pieces of hardware. Has anyone else had this problem?
It turns out the reset line has a 10K pullup resistor but no capacitor to ground. That explains why it occasionally worked.
Mike