Use -F to override this check - How to do it ?

Development Tools Uploading
3

Hi @papi_78. The first thing I should say is that, in 99% of the cases, using the -F flag will not solve upload failure.

I feel the need to point this out because the question of how to use the -F flag comes up here on the forum regularly and so others who want to do that in other contexts will likely find this thread during their research. Most of the time when people see this it is because communication was not established with the target chip at all (either due to bad wiring or permanent physical damage to the chip) and so a garbage signature (e.g., 0x000000) was read. Alternatively, it might be that the user accidentally selected an inappropriate board in Arduino IDE and the signature check is working as intended. In either of these cases, the suggestion to use the -F flag is a "red herring" which will only distract the user from more productive efforts to fix the problem that caused the signature verification failure.

It sounds like yours might possibly be one of the rare cases where there is some logic behind overriding the signature check. Since we don't have any confidence this will help, the best way to proceed is to run the avrdude command from the command line terminal rather than spending time adjusting the ATTinyCore platform's configuration files to add the -F flag.

:warning: The signature check is there for a good reason. Overriding it might result in the target being put into an unrecoverable state, or cause permanent damage. You should only override the check if you know for sure it is safe, or are willing to accept the loss of the target hardware for the sake of the experiment.

If you wish to proceed, try this:

  1. Select File > Preferences... (or Arduino > Settings... for macOS users) from the Arduino IDE menus.
    The "Preferences" dialog will open.
  2. Uncheck the box next to "Show verbose output during: ☑ compilation" in the "Preferences" dialog.
  3. Check the box next to "Show verbose output during: ☐ upload".
  4. Click the "OK" button.
    The "Preferences" dialog will close.
  5. Attempt an upload, just as you did before.
  6. Wait for the upload to fail.
  7. Examine the contents of the black output panel at the bottom of the Arduino IDE window. There you will see the avrdude command Arduino IDE generated. Select the entire text of that command.
  8. Press the Ctrl+C keyboard shortcut (Command+C for macOS users).
    This will copy the selected text to the clipboard.
  9. Open a command line terminal.
  10. Paste the copied command to terminal prompt.
  11. Append -F to the command.
  12. Press the Enter key.