I believe that the VMG8924 uses the BCM631
68 as opposed to the BCM631
38, which would be the issue. The BCM63138 is a newer chip, featuring G.fast support and Wireless-AC integrated. If they did include the BCM63138 it is puzzling to me as why would they release a unit with G.fast support then disable it?
A possibility is that because the spec is being updated and has not yet been finalised, they may have disabled it so as to keep it as a single chip solution. However, at the same time, the lack of the
xdslctl info --RNC_QLN
command suggests to me that they have instead gone for a dual chip solution, choosing to use a separate chip for the AC wireless.
It would be nice if someone could open up a VMG8924, as I cannot find details of precisely what chipset it uses.