The Dreaded stk500_getsync() message…

Everybody wants flying FPV quadcopters at  some point wants to see the cool telemetry showing up on their FPV goggles.   If you are building our own, then most likely you might have bought one of the Minim OSD modules from Amazon or Ebay and watched the YouTube videos where they show how easy it is to download the MinimOSD sourcecode, launch the Arduino IDE and click the little check mark to push code down to the MinimOSD module.


Yeah right!  Nothing is ever that easy.  Chances are you will first struggle with getting the USB to TTL module drivers loaded onto your computer.  You can thank Microsoft for making this even more challenging on Windows 10 because you have to go through the process of enabling “Unsigned” drivers to be installed.  Apple is not without fault here either as I have to use a cheap USB 2.0 Hub between my MacBook Pro and any of the USB modules to get it to reliably connect.

usb to ttl

Once you get over that hurdle, you can count yourself as one of the LUCKY few that actually get to have a successful MinimOSD compile and upload, but for most they are seeing this image at the bottom of the screen of their Arduino environments:

avrdude synch timeout

I had gotten one of these and searched YouTube for an answer which pretty much told me not to worry. All I needed to do was to make sure I had selected the correct board and com port and all of my troubles would be gone.  Once again, I was not one of the lucky few.

Getting the message, stk500_getsync() means that I am unable to connect to the bootloader on the module.   The bootloader is a small application running on the MinimOSD that first looks to see if we want to upload new firmware and then if not, executes the firmware it has in memory.  If this bootloader some how gets corrupted then all you need to do is to install a new one.  You will need an AVR ISP Programmer and temporarily solder 6 pins into the 6 holes that you see that are on the MinimOSD module but are not being used.

minim with pins

Atmel Studio 7 with a “fully supported” programmer is the most consistent way to do this or you can find a much cheaper ISP programmer on Ebay and use the avrdude commands from a command line.  While this might seem like extra work, knowing how to do this is a skill set that every one flying quadcopters should learn because it will save you time, frustration and money in the long run. I will tell you that I have tried to use Extreme burner and it only led me to false reporting of success.  If you can’t use the Atmel Studio 7, then just stick to the avrdude commands in a command prompt.  The avrdude commands will let you erase the module and let you upload a clean stk500v2 boot loader from your Arduino environment.  With that said, try to install the Atmel Studio 7 IDE to make your life easier.