Just as an off chance, have you double checked your hardware configuration. If the FICON card in the z/800 is a LX card (longwave) you must be plugged into an LX HBA card in the 2105 and you need a singlemode cable. If the FICON card is SX (shortwave) you need to plug into an SX HBA card and the cable is multimode.
Regards, John
