Homehub 5 - Slow VDSL speed


I have SKY fibre to cabinet connection and recently flashed a BT homehub 5 with OpenWrt 18.06.1 r7258-5eb055306f / LuCI openwrt-18.06 branch (git-18.228.31946-f64b152) firmware.

Everything is working great EXCEPT my connection speed went from 78-79mbps with the sky router to 64-66mbps with the openwrt homehub 5.

Is there anything I can do to increase my connection speed?

This is a known limitation with the HH5A. Openwrt doesn't make use of hardware NAT on that device and so its top speed is limited by the CPU. My advice would be to get an edgerouter x as the router, and use the HH5 as an AP.

Also see here: https://openwrt.ebilan.co.uk/viewforum.php?f=7&sid=1d2becb7175ca90bc88c9994c87e1564

Is 64-66 mbps the actual DSL data rate reported by the HH5A, or the speed measured over wifi ?

18.06.x also suffers from noticeably degraded maximum WAN-to-LAN throughput when compared to 17.01 due to a commit introduced in February 2018:

Other devices might be affected too but I've not seen any wide spread reports.


Yes, the 64-66 mbps is what the HH5A reports and connects to.
Data Rate: 63.329 Mb/s / 19.978 Mb/s
Max. Attainable Data Rate (ATTNDR): 68.511 Mb/s / 25.599 Mb/s

As I said with the SKY router it connects @ 78-79 mbps so was hoping I could get the HH5A modem to connect closer to that speed.

Differences may be attributed to different chipsets and compatibility with your line. Sky uses broadcom, HH5A uses Lantiq.

If you don't have a 'filtered' Openreach master socket, does plugging HH5a into the hidden engineer's test socket make any difference to eliminate any local internal wiring issues?

You could try a later Lantiq firmware file, but I doubt it will make much difference unless you happen to live in an area where Vectoring was trialled on FTTC cabinet and was never removed. See section 7.27 of the installation guide for HH5A.

Thanks for the reply. It is not convenient to have the router where the line enters into the property so I cannot move the router.
I was with BT on the same line before I moved over to SKY and used the exact same HH5A that is now flashed and got 79/20mbps so I don't think it is hardware related.

I guess I will just have to either put up with SKY router @ 79/20mbps and have ethernet dramas OR HH5A @ 64/20 with no ethernet issues.

Browsing the GPL source code for a recent version of the Netgear DM200 OEM firmware (v1.0.0.52), which uses the same chipset, I found references to some xDSL driver parameters being tweaked for UK based VDSL services with the comment "All UK ISPs need these commands". The file in the archive is named dsl.sh and there are 2x dms and 1x dmms parameter sets (sorry, can't copy/paste at the moment) specifically for UK VDSL services. I don't believe OpenWrt's stock equivalent is setting any such ISP specific xDSL parameters. Whether these parameters affect the sync rates you get I don't know.

If you haven't already done so, you might also want to try a different (later preferably) version of the xDSL driver file as I believe the file included in the 18.06[.1] firmware is quite old - see https://xdarklight.github.io/lantiq-xdsl-firmware-info/ for some references.

Also, if the Sky modem uses a Broadcom chipset it could easily sync at rates 5-10% higher than the Lantiq chipset. Your results show a difference a bit more than that but similar to the difference I experience between a Fritz!Box 7490 (also same Lantiq chipset) and several Broadcom based modems.

Thanks for that. All good info there. I will have a tinker when I get a chance, hopefully this week.
I believe it is a software/driver issue because as I said before when I was with BT and using the exact same Homehub5 (stock firmware) before flashing I was also getting 79/20 mbps.