Replacing faulty processor


Has anyone replaced the processor with another one? Data pin D+ on the USB port is putting out 3v as of last night now I am getting a device not recognized. I don’t know what happen I erased the sketch with the erase button and some how it nuked my USB. I think my situation is isolated but has anyone encountered this? I ordered a new processor from Digikey $11 to replace it hopefully my SMD soldering is up to snuff. Do I need to burn in a arduino bootloader on the new processor so arduino software will recognize it or will everything work fine just plug and play? I just don’t want to have to pay $50 for a new processor board.


Getting a processor off of a board is not usually a very fun thing to do. There are a lot of pins on there! The two best solutions are a hot air rework station or chipquik. Thereafter if you have a stencil, solder paste, and a reflow oven (or hot air station) that would be ideal. Otherwise it tends to be easiest to solder all the pads first (lightly), apply flux to both the processor and pads, and then use a soldering iron to heat up the feet on the processor to melt them down to the pads below. It’s not a lot of fun. A hot air rework station could work here too.

The good news is that the bootloader is permanently burnt into the ROM on these chips so there is nothing you need to do to make it work. The chip will come up as Bossa when you first install it and access USB and then you just program it like normal.


Unless you did something to physically damage the board I suspect you just cleared the memory… You erased the memory on the board and now you need to reprogram it. It will show up as a different device.

Try this… Open device manager for the serial devices with the unit unplugged. Plug it in. You will see a USB port added. Unplug, you will see it go away. You just need to use that port number to reprogram the board.

This is normal operation. On mine it will show up as a M2 on like port 6 when programmed but show up as the Bossa device on like port 12 if I do the erase of the memory.

Before you go through and do anything crazy just try to find the new port and reprogram it and you should be fine.


Hey @brianbri6,

If you discover that you did in fact fry your processor board, we’ll send you a new one. You’ve been very involved in the community here, so it is the least we can do to thank you!

@redheadedrod has a very valid point though - it could be that you just need to re-flash to a different port.

And @CollinK is absolutely right! It will not be fun to replace that part without hot air rework station.

Let us know what you find out.


I definitely do appreciate it Josh I was pulling my hair over this! I will PM you for return details. I replaced the processor but it is 50%/50% now. When I plug in the USB or OBD2 port it doesn’t do anything, no power nothing until I touch one of the oscillator capacitors C13 or C14 with my bear finger to get it to power up weird! It’s repeatable when you power cycle it, no power then touch C13 or C14 them boom its alive. :thinking: Thank you everyone for your help and support you people are a great group.