- Bootloader corrupt, AVR lock bits on, preventing firmware flash verification. Also Blank check fails.
- Bad Firmware causing printing issue. Too many different firmware's out there.
- Used Bus Pirate / avrdude to reset lock bits and reflash DFU bootloader.
- Re-flashed working firmware (RevF4-v1-SimpleMetal.hex attached zip file. After trying so many different firmware files, don't remember where this one came from)
Since this was a software issue, mods may move it to correct location. Thanks
I am working on gathering some other instructions and PIN layouts that I will attach to this post when they are done.
*** Original Posts Below ***
So I had to re-flash my boards firmware and now having odd issue. Board is F4 and used firmware simple-0.6.hex from Printrbots Github.
So while printing at random times during print getting a noise like motor is stuck and hotend keeps extruding in same spot. This only started happening after firmware update. I checked my M212 settings and same as before firmware flash.
Prints will complete if I keep retrying.
Belts look good and tension is good. Thinking I may have used wrong firmware, not sure.
Thanks for you help.
** Update ***
Went to reflash firmware again and now getting Blank Check failed. So sounds like board may be shot.

So flashed it with RevF_v5.hex, left blank check and verfiy unchecked and it seems like it flashed. Testing print now.
Making progress, Print finished, but part way through paused with loud buzz for 15-20 seconds then started up again.