Is DSL unstable on Fritz!Box 7412?

According to an article on (, the DSL modem is not stable enough for daily usage? Is that true or rather a misconfiguration by the authors (it is said they tried three different DSL accounts). Thank you.

It's hard to comment on what an article says if it's hidden behind a paywall. DSL under OpenWrt is indeed not completely rock stable. There's a long-standing and still unresolved bug that fudges up something somewhere between PPPoE and the modem interface, and it seems to happen more frequently to some people than to others. That being said, for most people, on most lines, under most conditions, for long stretches of time ... it's plenty stable as a daily driver.

"Zwar unterstützt OpenWrt auch das xDSL-Modem der 7412, die Funktion erwies sich in den Versuchen an unseren drei Testanschlüssen jedoch als instabil und für den täglichen Gebrauch ungeeignet."
Thats all it says (and this sentence is also visible in the preview). There is no further mention of dsl usage in the full article. Maybe the bug is related to certain hardware revisions?
I guess it's save to give it a try and, in case it doesn't work, it is always possible to reflash to Fritz!OS, right?

Yeah, that's precious little to comment on. They don't say why it is unstable, or how the instability presents, or how frequently it occurs for them to make such an assessment. There are plenty of people running DSL on OpenWrt (including myself, on two very different lines) without any major issues. Again, minor issues can occur, but that's par for the course for any router really, and it's a far cry from "unusable."

And both OpenWRT devices you are using are 7412?

No, but they are siblings in the same "Lantiq VRX200" chipset family. One is a TP-Link W8980 (VRX268), the other is a Fritz!Box 3370 (VRX288). And they are all running the exact same chipset code as the the Fritz!Box 7412 (VRX220, which, despite the lower number, is actually the newer chipset revision).

Thank you. Still a different revision, though.
Maybe someone else with a 7412 here? I guess I will try OpenWRT anyways (once I managed to extract my full 1&1 credentials from the capture logs:))

Just read a comment in the comment section of the article mentioned above pointing to
Seems to rather be a firmware issue which was solved already.

my 7412 is running right now in prod system (thx @eomanis VDSL+VoIP Fritz!Box to OpenWRT-on-FB-7412 migration cheat sheet). VoIP (Telekom) is working via 7560 / 7560 Mesh setup). seems to be stable.

There seem to be at least 2 variants of the AVM FRITZ!Box 7412 around:

  • Part number 20002698
  • Part number 20002759

At the photo at the bottom of the migration cheat sheet you can see that the units look slightly different, the right one having an additional "1&1 WLAN-Modem VDSL" print on the front below the FRITZ!Box logo.

Despite this, they are both part number 20002759.

I have been using this exact setup since the time I wrote the cheat sheet, and the VDSL synchronization appears to be at least as stable as with the stock firmware. Right now, /etc/init.d/dsl_control status reports a line uptime of 4 days, 8 hours.
I have not noticed any upload-stress-related reconnects as described in the linked bug.

This speed test just now gave me these pretty sweet results:

  • 92.9 MBit/s downstream
  • 34.3 MBit/s upstream
  • 10 ms ping
  • 4 ms jitter

This is with a newer firmware version (VDSL 9.1.4, from the FRITZ!Box 7490) than the one from the cheat sheet (VDSL 9.0.C), which has been added to the xdarklight listing in the meantime.

In summary, on the variant with part number 20002759, both these firmware versions have been working well for me, both being equally stable, with the newer version reporting a somewhat higher Max. Attainable Data Rate (ATTNDR) and subjectively seeming less CPU-bottlenecked at intensive downstream usage.

I do have a spare FRITZ!Box 7412 that has the other part number 20002698, I guess I could put OpenWRT on that one and see how that works out.

I have 2 boxes also. They look like yours (one without the additional printing Part number 20002759) and one with printing ( Part number 20002698). I installed openwrt on 20002698.
I only have trouble with VoIP. It breaks after ~15min (typical FW problem I guess). I extracted firmware 9.1.4 (I was not able to decompress firmware.image from latest beta FritzOS 7.19) und will test it, once i solved the VoIP issue.

update: 20002759 can be reverted to FritzOS by fritz.box_7412-06.86-recover.exe. My VoIP issue was caused by missing IP forwarding (uci-commands did not work, Luci-config worked). firmware 9.1.4 runs stable.

Any update concerning the stability on the two variants?

  • Part number 20002698
  • Part number 20002759

my box is running > 60days, I had one or two disconnects in the beginning (while also playing around). but since > 40days I am connected (with same IP). neither my family nor me observed any issues working from home. I am connected via VDSL50 with average 20gig traffic / day (up to 30gig: 20-25 down, 5-10up).

Yes, that is a very common timeout issue if your VoIP client is behind a firewall. It can be remedied either with the VoIP client, usually setting it to actively keep the connection alive, or with port forwards to the VoIP client (if it is on a static lease/static IP). Fritz!Boxes are almost guaranteed to need it, see also this knowledge base article for the Fritz!Box (in German) -- but up until now I got away with just setting them to keep the line active.