OP...I assume you have the BMW OEM headrest system...concerning the b&w issue, the trouble shooting pages in the manual describes this as resulting from the DVD unit overheating. I've experienced this issue and took the system apart to drill down on the cause...also had the system inspected by audio/video techs at dealer. Even after new headrest monitors and wires, it still played in b&w. The techs believe the culprit is in the DVD unit itself. They claimed a "burnt module"...eventually one of the monitors stopped showing pictures. I swapped with a friends unit and even purchased a new DVD unit but the issue persists.

Since the dealer techs were unable to pinpoint the root cause, i found an independent specialist that claims he can either pinpoint the issue or consult on remedy. I plan to make a final attempt to resolve when the weather warms up. Keep me posted and i'll do likewise.