So just to be clear, you have brought up 2 issues:
- The bad date code switches
- Inability to update the firmware
The bad date code switches have a wiring defect which impacted the range of the wireless signal. Flashing to a new firmware will not resolve that. But since those switches are joined to your network, it sounds as if you don’t have to worry about the signal issue.
The harness will only solve the inability to upgrade firmware. That’s due to an older bootloader. Upgrading the firmware via the harness will replace the bootloader and you’ll be able to OTA firmware going forward.