I’m not an expert. I’m just relaying information that I’ve seen at HDD Guru and in private communication with data recovery professionals. That said, I wouldn’t be certain of anything, as the pros even disagree amongst themselves. FWIW, there have been some recent posts at HDD Guru when end users have successfully swapped the bridge boards without any firmware transfer. However, I’m not sure about the criteria for a successful swap.
That said, sometimes there is an easy fix:
http://malthus.zapto.org/viewtopic.php?f=100&t=155&p=642
