Well, the ECB is, in fact, funding Greek banks using GGBs as collateral. However, technically GGBs are money good at the moment. Moreover, the ECB is imposing haircuts, which are relatively punitive.
I had to impression that the ECB had taken the 'more toxic' GGBs as collateral and even that they had bought them and are now the owner? Are there non-standard GGBs which the ECB could now be responsible for liabilites over and above the standard?