Artemis Red Nano bootloader not working on Mac OS X Sequoia 15.1

Hi folks!

I recently upgraded by Mac to Sequoia 15.1 and now I am unable to flash my Artemis Red Nano. It says the SVL Bootloader does not work. I verified the bootloader does work by using another Mac with an older version of the OS. The Serial Monitor does work, however, so I think the serial port configuration is OK. Has anyone else seen this or have a fix?

Here is the output from the Arduino IDE:

Artemis SVL Bootloader
Target failed to enter bootload mode. Verify the right COM port is selected and that your board has the SVL bootloader.

Thanks,
Karl

Someone the other day posted they had to enable unkown dev mode; see if that helps yours?

Thanks! Sadly, it did not fix it. I think that Security setting is for running apps not coming from the store or from known developers. And the app runs just fine.

Had this issue and spent the day debugging it. The bootloader expects an RTS signal from the USB on every new initialization. This doesn’t happen with the macOS sequoia operating system (it probably will once they deal with various security configurations), so if you add two lines of code after calling the serial command in svl.py, ser.rts=FALSE then ser.rts=TRUE, it sends the ping that initiates the bootloader and you can upload code to the board. Easy patch that should correct any issues with USB drivers in future.

also, if you take the new script, turn it into an executable file in the arduino filepath, you can upload code easily through the Arduino IDE if that is your preference!

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Thanks Farrell! This is great stuff! Where is the svl.py file stored? I’m not using Python for the Artemis board. Or are you saying I should create a Python file on the Mac side, run it, then I can download my binary using the Arduino IDE?

OK, I found the svl.py file in the Arduino15 library path and where it tries the serial port. I made the changes but don’t see the Arduino IDE running the script with my changes when i try to upload code to the board. How do I “turn it into an executable in the arduino filepath?”

Sorry couldn’t respond until now, I wrote a tutorial for my students, let me know if you can’t access the site or if you have any questions! CH340 USB to Serial Communication | FastRobots-2025

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Thank you so much! I can access the site. The direct download link for the svl file is out of date, but I found it by navigating the github site. Ironically, I am following your course and building my own robot car at home! My son took the class last spring and then bought me the kit of parts for Father’s Day. He pointed me to the github and said “some assembly required!” :slight_smile: Thanks again!

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I made the changes, compiled the python file, and now I can upload code to the Artemis! Back to the robot! Thanks again!

So happy for you! Let us know if you have any other questions (preferably not on this site, I am very slow to respond here, sorry!