Xizhen Du (#22): You must always state the exact URL you used. My guess is that you used one from .../precise/... rather than .../precise-updates/..., which means you're effectively using 12.04.0 rather than 12.04.5. There are up-to-date files linked from http://cdimage.ubuntu.com/netboot/precise/.
Xizhen Du (#22): You must always state the exact URL you used. My guess is that you used one from .../precise/... rather than .../precise- updates/ ..., which means you're effectively using 12.04.0 rather than 12.04.5. There are up-to-date files linked from http:// cdimage. ubuntu. com/netboot/ precise/.