Hello Rainer, I think this is the memory map of the ethernut 2.1: 0x0000 - 0x7FFF SRAM 0x8000 - 0xBFFF SRAM Window 0xC000 - 0xCFFF NIC 0xD000 - 0xFEFF Free 0xFF00 - 0xFFFF Page Register @Harald, can you confirm this? Regards, Michael