I may well have go things wrong. To be honest, your message is a rambling mixture of sometimes conflicting, and often confusing, statements, so I had to read between the lines.
Why did I point the finger at BT? Or, as you put it:
I do not understand your linking of the problem with BT
Because you wrote:
we are on the former BT telephone system
Perhaps naively, I thought that this meant that you were on the BT network but had TalkTalk as an ISP. That's my position. (Many ISPs do not much more than tag on to the BT system at the exchange and then take over from there.)
In the rest of that sentence you write:
we are on the former BT telephone system which of course has been upgraded to FTTC
The BT telephone system has not be upgraded to FTTC. Some bits of it have, mine hasn't. So there is no, "of course", about it. Your bit, maybe. But that blanket statement is confusing, to say the least.
The bit where you write:
although a speed of 6.1 Mbps D/L is hardly anything to shout about, the performance and stability now is brilliant, thanks to the D6400.
suggests something seriously wrong, if that really is the speed you see. (How are you testing that?)
I get >7 Mbps on my BT ADSL line. The speed you get is taking the p*ss for FTTC/VDSL.
This bit is also strange:
the latest upgrade indicated on the Netgear Genie is V1.0.1.22_1.1.22. this leaves me confused as it does not appear on the Netgear upload site.
Again, what does not appear on the Netgear download (I assume) site? V1.0.1.22_1.1.22?
V1.0.1.22_1.1.22 is probably the one at release. (Yes, Netgear has a habit of billing firmware in different ways.) There have been two since then. The best place to look for the firmware is to ignore the standalone Genie and go into the modem's own web interface. Then in the Advanced > Administration area look at the Firmware update bit.
I am not sitting at that modem at the moment – it runs the network indoors not in my office – but if you can navigate your way through Netgear's crummy support system you may land here :
NETGEAR Support | Downloads | D6400
Then you will see that as well is listing
Firmware Version 1.0.0.22 (Initial Release)
it also has two later firmware updates:
Firmware Version 1.0.0.34
Firmware Version 1.0.0.38
The first of these wrecked the D6400 for quite a few people on the BT telephone system. (Some BT customers, other TalkTalk or some other ISP, such as PlusNet.)The second firmware restored our sanity.
I'm with you on not messing around with things that seem to be working. But as I said, the download speed you are getting is pathetic for an FTTC (VDSL) link. Maybe a new firmware will get something nearer to what you are paying for.
You can always download the older firmware, which is probably the same as the one you have installed, and then go back to it if the update ruins your life.
