I honestly think it's just a guessing game. Like I've never found anything that said what firmware to use, I just try all 6 available (resetting from the same save) until it works. The only exception is I did find Site Zeta's, while at site Zeta.
The ESR suit protects the wearer during inter-dimensional travel. It’s apparently so high-tech you have to ensure your firmware is compatible with the destination.
