If the byte order isn't right, just send the bytes through Serial in the right order.
all this does is to make [3] and [0] equal whatever [0] was and make [1] and [2] whatever [2] was. 12.5 gets 0's.
block.bytes[3]=block.bytes[0];
block.bytes[0]=block.bytes[3];
block.bytes[1]=block.bytes[2];
block.bytes[2]=block.bytes[1];