Difficulties when burning bootloader with Arduino as ISP (Mini/Mighty/MegaCore)

See MiniCore #115 for more details.

It’s impossible to set the upload baud rate for the bootloader when burning bootloader with Arduino as ISP. this is because ArduinoISP relies on upload_speed = 19200 to work. However, when this is specified, a bootloader with a baud rate of 19200 is always selected, no matter what board_upload.speed is defined to.

• board_upload.speed should be used when doing “regular” uploads using -carduino as upload protocol (using a bootloader).
• upload_speed should be used when the user is uploading using a programmer to upload, or setting the fuses/burning bootloader.

This is only an issue with programmers that uses a serial port and a baud rate to communicate with Avrdude. @ivankravets @valeros I guess it should be an easy fix.

[MCUdude]

Not sure about this, board_hardware.uart option is mainly used with your cores and upload_flags option might be used for UART upload as well. Besides, in most cases burning fuses/bootloader is one-time operation, right?

OK, at least my idea is not thought through yet. We can leave this for now and focus on the other thing.

In the most cases, it’s not an option since board_upload.speed is always present (set by a user or default value from a board manifest).

Yes, that is right, sorry. Then I think we agree. Use board_bootloader.speed is present to get the correct bootloader file. If not, use board_upload.speed. OK?

[MCUdude]

Thank you! Will give this a try very soon. I’ll report back if I find any issues 🙂