It seems Arduino is not using the command defined in “tools.avrdude.program.pattern” in platforms.txt and I guess it should. Very likely this is the actual issue. Why it is not using that command, I have no idea.
Possibly relevant: Arduino upload instruction ignores changes to platform.txt
Ok, figured it out: User error due to a terrible Arduino IDE interface.
Here is what I did:
- Opened Arduino IDE for the first time.
- Set programmer to USBTiny ISP.
- Installed Blinks board files.
- Opened a Blinks project.
- Tried to upload it.
The problem is that because I selected the programmer before installing the Blinks board files, The USBTiny ISP being used was from the previously selected platform (Arduino Yun, the default) so it would not pick the correct flags.
Selecting the Programmer again after installing and selecting the Blinks board fixes this.