That's right. It changed as soon as G.INP came back on my upstream 2 weeks later.
AFAIK the upstream was turned off completely until recently, the new rollout though may well of been tweaked so that DSLAM's take into consideration CPE's chips and compatibility.
I know that upstream retransmission wasn't enabled on my line in December before moving home, and my line was one to get it and then lose it when the fix for ECI/Lantiq problems was rolled out...
So the point here is that Lantiq chipsets do support G.INP.... TP-Link confirmed that and I'm almost sure that the same xDSL chip in the TP-Link W8890 matches that that is either in the ECI modem or the BT HH5a (and potentially PN H1)
Whether any updates to Lantiq based products has been done to make it further capable with G.INP (Upstream) I'm unaware though have seen a recent post with regards to some sort of upgrades to the ECI DSLAM's