This is a tracking issue. There was a mistake not pulling up /HWB externally, see http://www.sowbug.com/post/21718480349/avr-programmer-hwb-and-hwbe, but I think the better resolution is to do it in software as Dean suggests, or else to go with Adafruit's timed bootloader approach.
This is a tracking issue. There was a mistake not pulling up /HWB externally, see http://www.sowbug.com/post/21718480349/avr-programmer-hwb-and-hwbe, but I think the better resolution is to do it in software as Dean suggests, or else to go with Adafruit's timed bootloader approach.