I have no way to know what you did that may or may not have caused problems. It wasn't the firewall.
A manual upgrade looks like manual upgrades to most firmware-based devices: you download the replacement firmware binary file to your computer, then you go to the OBi device's built-in web page, point it to the location of the file, and then the device uploads the file to its internal memory. After that, the upgrade runs, erasing, re-writing, and verifying the firmware on the device's flash memory. This should take just a couple of minutes. While it's happening, the power LED will blink, and after the LED settles down and stops blinking, the update is done. At that point, you should be able to log back into the device and see the firmware build information on the Status page.