i don't fly the 800's but I imagine it would be pretty much the same, happy to be corrected.
In the -800s at 10,000 feet the Cabin Altitude is 1000 feet and the DP around 4 psi.
I'd say the -800 series had wiring, pump and duty cycle improvements but I doubt they had inerting.
In our fleet, 2 aircraft [leased ones] had the old pumps, so we have to leave 500 Kg in the Center Tank at all times. All the other ones have the modified pumps with the Automatic shutoff. The aircraft delivered after 2008 all have the NGS inerting system installed.
I hope they find the CVR Memory module soon. Chances are it might have been covered up by silt. Any idea how they are searching for it??
Cheers