> Open On-Chip Debugger 0.11.0 You're using a very old version of OpenOCD. You should probably use a more up to date version.
> Error: invalid subcommand "write_image erase a.elf" Isn't the correct command, at least for the current version of OpenOCD, as follows: flash write_image erase a.elf See the documentation: https://openocd.org/doc/html/Flash-Commands.html I suspect that your openocd-due.cfg script file is mismatched with your 0.11.0 version of OpenOCD and uses commands/command formats that this older version doesn't support.
