JFC – why are you doing that?
disable battery, run script, script disables SW WP, prompts you to reboot
run script, flash firmware, power off, reconnect battery.
the instructions explicitly say not to run any flashrom commands manually – for good reason. If you don’t reboot after SW WP is disabled, there are still parts of the flash protected by another mechanism – which is why the erase is failing.
You can just restore the stock firmware via the script and reboot, then re-run/re-flash and it should be fine