Just been hounding the Engineers next door. They advised that the 2 units CVR/FDR are housed within the same enclosure they sit on a rack and have 2 knobs on them to detach the unit (hope this is making sense). It's not unusual for them to be come separated. The FDR will advise A/C speed, altitude, bank angle, pressurization to name a few. The CVR will provide the last 0030 minutes of conversation between the CAPT and FO. The Engineers advise that the CVR will still record if you are flying on 1 engine. If an A/C has lost both engines it will not record.
Thanks Emirates, bbm. What? We have to get better than that. just venting.