How does that impact the investigation?
I'd say quite significantly. Can someone confirm that the FDR CB is indeed in the EE bay and that the FDR cannot be disabled from the cockpit by pulling other CB-s higher up the power grid ?
My assumption was that whoever initiated the departure from the original flight plan (and there IS consensus this must have been intentional, though most likely the last hours of the flight were purely on autopilot) with an objective to hide all traces would start by pulling the FDR CB, followed by all comms systems. If this is not possible, the FDR might indeed hold some clues on at least the initial sequence of events.