If you're using my fork, I've stated that (which you should be, considering you have b9s now).
"If you get stuck on the loading configuration file or get an error message such as "Unknown or wrong config value", either delete the lumaupdater.cfg file on the root of your SD card or change the payload type in the first line of lumaupdater.cfg to payload type = SIGHAX and payload path = boot.firm."
Also, MattKimura is right. However, I may have a fix but I won't be able to test it until the service Luma Updater uses shuts down.