Nikon D1 - no silent upgrade
But certainly a repair for some owners... Thanks to the investigative work of Rob Galbraith we seem to have an answer to why some owners have D1's with the high ISO banding problem and some don't. "...there is no so-called "silent upgrade" for the Nikon D1 that magically transforms its high ISO performance. But, some D1 cameras may require the replacement of a failing electronic part to rid images of a slight to noticeable diagonal pattern, especially in the green channel of images shot at ISO 1600 and above."