I have all my devices (RME + speakers) plugged into a master/slave socket block so they all switch on together. Since upgrading the firmware from 135 -> 138, there is a loud audible pop when powering the system on that seems to be emitted by the Fireface (especially given it started the moment I updated the firmware to 138, after having the prior setup on 135 for years).

My guess is the old firmware either started up faster, before the speakers could even play the pop, or there was a deliberate (or accidental) one second (or so) mute when the device first powers up on the old firmware. Either way, I would greatly prefer the Fireface system did not emit such a noise each time it powers up. Is it either possible to downgrade the firmware or to release a new firmware with this issue fixed?