Just deployed my U2415 using DP passthrough to an HP ZR2440w.
AMD R9-280x mDP out -> mDP - DP adapter -> DP cable -> DP in on U2415 -> DP out on U2415 -> DP cable -> DP in on ZR2440w.
Worked great, until the U2415 went to sleep!. The U2415 woke up, but the HP wouldn't. Had to power-off and power-on the U2415 to restore function.
Back of monitor states REV A01. Is there updated firmware available for these? Is it field-upgradable or do I need to RMA it?