Maybe try it this way:
1. Don't run any script from OP.
2. Then add/keep the short and connect the USB.
3. Now take a look into lsusb:
- If you get MediaTek Inc. MT6227 phone message, run the bootrom-script with sudo...
- If you get something with preloader, unplug the stick and try again.
- If you get no message at all in lsusb while keeping the short, the BR-Mode is disabled, OP wont work for your stick.