BT Infinity and my HG612 VDSL2 Modem Firmware Upgrade

My Home Download Speed

Warning: If you attempt what I describe here you may reduce your modem's usability to that of a brick , remember you are in charge of your own destiny. Note: I have two modems one for experiments and the other as backup.
 
I have been in the habit of using a Raspberry PI to log my ADSL2+ then VDSL2 speeds for a while now. The graph above is the speed of my ADSL2+ until I got BT Infinity or FTTC (Fibre To The Cabinet) , the time is about a year in span and speed is in kbps. Point A is when my ADSL2+ speed a took a dive due to a tree wearing through my overhead telephone line. It took BT about a full month to fix the fault and remove the subsequent speed cap at Point B , it took two emails to the BT Community Forum to get them to remove the cap even though they said that it had been removed , it hadn't.
Between Point B and C you can see my speed was unstable with my router continually dropping connection and then re-syncing at different speeds. You can see how unstable it was even after the line repair compared with the lead up to Point A , perfect. I then had BT Infinity installed at Point C using a BT Openreach Huawei EchoLife HG612 modem with unlocked firmware. This allowed me to log speeds , it isn't something that is enabled by default with BT's stock modem.
Between Points C and D it is not very stable speed wise , I have a long wire to the cabinet hence the lower than anticipated VDSL2 speed. So eventually I got a bit fed up with the variability of the connection speed so I tried new firmware in my modem , this firmware has a newer binary blob driver for the Broadcom modem chipset. Point D shows the time the modem had the new firmware flashed , it is a higher speed and also very stable , fantastic. So the only thing that has changed is the firmware change on the HG612 at point D. This also just shows that the digital signal processing elements have been improved in this binary blob driver.  Now I'm very impressed with the latest firmware for this modem , but it's a shame I've had to do all this firmware upgrade myself and that BT don't seem to be continually improving their modem firmware. This even though they do have BTAgent enabled to update firmware themselves.
I have BTAgent disabled because I don't want them to disable my logging system with their new firmware. They seem more concerned with not allowing their customers to actually see how bad their broadband connections are by disabling useful functionality. It has been noted by others that some of the BT firmware updates rolled out via BTAgent have disabled Web Configuration and telnet access to these modems.
Hope this helps you.