This is how the whole card sharing stuff happens..
If you have a genuine sky card you can set it up in your Linux e2 box and share with as many boxes as you want or need too depending on correct set up..
Of course you can only now share SD channels and the few fta HD channels but it's a way to use your one card in different boxes around your home.
well in a nutshell you can simply use your upstairs box to stream/use one of the free tuners on the duo2 its done over your network..
To watch TV with a good picture quality one could very well use another box with the "Partnerbox"-plugin. This second box doesn't need to have a dish connected; a LAN-connection to the "main-box" and an HDMI-lead to the TV is sufficient. Watching recordings from the main box is identical to doing that on the mainbox itself; watching live-TV goes via the partnebox-plugin.
For this purpose the cheapest box accepting the partnerbox plugin will do. If you want to be able to watch HD-TV (-recordings) that box must obviously be HD-capable.
easy way i think is to set up a share from your duo2 ie share duo2 capabilities .there is a tutorial on here somewhere i can not find it..like C\S