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.
The interface in front of the suit allows you to choose which firmware and coordinates to program the suit with. You then wear the suit before entering the rift in the Lvl3 card room. If done correctly you will be teleported.
