Trying to change firmware on Convoy S2+ driver

Hello, this is my first post to the forum.

I recently bought a Convoy S2+, and I am not happy with the firmware on it. I would like to replace it with the Biscotti firmware. I have removed the driver, and am trying to use avrdude to interact with the MCU, but it does not seem to be recognizing it. I am fairly certain that I am doing everything correctly on the computer. I have tried doing it with a usbasp programmer, and I have also tried doing it by connecting the GPIO pins on my raspberry pi to the pins on the MCU. I get the following error:

avrdude: AVR device not responding
avrdude: initialization failed, rc=–1
Double check the connections and try again, or use -F to override this check.
avrdude done. Thank you.

I am hoping someone can help me troubleshoot this. Perhaps I need to do something to the driver like cutting a trace or soldering something?


1) clip isn’t connecting properly, try moving it around a bit, disconnect, connect again. this is fairly common. (just to be on the safe side - it is on there the correct way around? clip fits both ways)
2) did you build the cable or was it ready to use? I had to build mine and accidentally switched two wires.

I am assuming you have the nanjg105D driver in there, that one should not have any clearance issues with the clip.

On new drivers 5 pin of mcu connected to ground. Cut this line and flash it :wink:

Hello, thank you for the response.
I have cut pin 5, but unfortunately I am still having the same issue.

Thank you for your response.

I have tried several times, moving the clip around each time. None of them worked. I don’t think the clip is my issue.
I built the cable. I am fairly certain that I have it connected properly.

another issue might be that the MCU is locked, but that wouldn’t result in that message IMO.

Had a locked MCU once and that wasn’t the error message. Maybe someone else can pitch in on that? I hardly remember that light.

If you're up for experimenting, I'd point you at biscotti-HD:

(there are many builds there other than biscotti so don't be confused by text that doesn't seem to apply).

It is essentially derived from the latest biscotti code but by adding some space savings it gets a turbo timeout (and some stability enhancements that most won't notice). Since I don't have an attiny13, that particular build of bistro-HD (bistro-HD isn't just bistro) is not tested though, which is why I say if you're up for some experimenting, but you're already flashing stuff (well, almost).

I had to buy two USBASP's and flash one with the other to the newest firmware, but they weren't the fasttech ones. Actually this does look similar to the error I had then. Also check your jumpers.


I am pretty sure that the usbasp firmware is not my only issue. I was not able to do it with the raspberry pi’s gpio pins either, which does not use the usbasp.

If I cannot get this to work, does anyone have a recommendation for a driver for the S2+ that I can program?

Are you saying this firmware has not been tested on the Attiny13? If I can get it to work I would be happy to do some experiments with it.

It really looks like a basic connection is not being made. That is the normal error for a mispinned clip or cable or when the clip does not seat well on the chip. Flashing on driver can be a real pain, often use my magnifiers to make sure the clip is down all the way and aligned with the chip legs.

Yes (Toykeeper's biscotti is tested on attiny13, biscotti-HD is not because I don't have any attiny13 driver), and the spirit of your reply is exactly right, it's more of a situation of maybe it helps out HD than helping out you, possibly both. Just something to try if you want either way.

You might want to try flashing one usbasp with another anyway, just to test the process. That's relatively simpler to get right, since the connection is easier. Then you'll have part of the chain tested and working.

If you flash with the latest version of the firmware you have to add a timing command to the command line as well…

avrdude -p t25 -B 3 -c usbasp -u -Uflash:w:%1.hex:a -Ulfuse:w:0x%2:m -Uhfuse:w:0x%3:m -Uefuse:w:0x%4:m

The -B 3 is the new needed part after the “upgrade” I did both of mine to get rid of a persistent error, almost wish I had left them alone.

Hmm, you must have updated more recently than me. I don't need that. Can't say I even remember where I found the firmware, but it looked fairly maintained. That was a little while ago now.