Note that this is unusable without a Mac address, BLOB and device key
Please read:
http://tinyhack.com/2018/11/21/reverse-engineering-pokemon-go-plus/
Please see the following github project which can reflash a Pokemon GO+ and extract its mac/private key/blob while the flash does work on newer phones you make need to use an older one to do the extraction like a samspung S5 mini.
https://github.com/Jesus805/Suota-Go-Plus
Using this information you can populate a valid secrets file link this to secrets.c in main, any file ending secrets.c will be ignored by git to prevent accidental upload.