I bought a Vigor 2927 and an AP906 about six months ago. I have never been able to get them to work together. If the AP906 is turned off then there are no problems with the stability of the 2927. When the AP906 is turned on then the 2927 crashes every few hours. The 2927 is set up to use mesh mode. Here are my latest findings.

For the last 28 days I have had the AP906 turned off. The Vigor 2927 did not reboot at all during this time.

Before that, there was a fortnight when the AP906 was turned on but the house was empty and so no clients registered on the AP906. The 2927 did not reboot.

Yesterday evening I turned the AP906 on and two clients registered on it. Within five hours the 2927 started rebooting again.

So, in fact, it was a waste of money for me to buy the AP906 as it doesn't work reliably with the 2927. Or should that be the other way round?! I am in touch with the help desk but we don't seem to be making much progress. They sent me an unpublished update to the 2927 firmware which I'm now using but it didn't make any difference.

Has anyone else had a similar problem? If so, did you solve it?

Here is my debug log:
> sys ver dbg

Router Model: Vigor2927ax    Version: 4.4.6.2 English
Profile version: 4.0.0    Status: 1 (0x959360d0)
Router IP: 192.168.254.254    Netmask: 255.255.255.0
Firmware Build Date/Time: Apr  8 2025 17:25:23
Router Name: DrayTek
Revision: 5803_5f281c6b9a drayos2015_V2927_4458_r5786_ccfae
Router serial no: 248005165124

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firmware exception debug info on cpu0

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 EPC=6020995c, Cause=2080002c, Status=1100fc03, BadAddr=6598c440, RetAddr=60206364
 exception id=11(CpU: Coprocessor unusable)
 exception occured in TASK Level
 task_id=161, SP=0x627a1150(3526 bytes free, 4312 used bytes)
 system tick =133393
 CURRENT_VERSION : 4.4.6.2_R
 get from address : 60017000 
 Dump CPU0 registers:

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 $ 0: 00000000 fffffffe 00000000 6305c79c
 $ 4: 65990840 00000000 6598c440 65971b40
 $ 8: 6305c79c 657d6e40 00000000 00000000
 $12: 0000005c 627a0caf 00000000 000000de
 $16: 6598c440 6584e440 00000000 00000000
 $20: 61f5df20 00000001 00000067 62e4b500
 $24: 00000000 60f96560 00000000 60218030
 $28: 62768f60 627a1150 632e0000 60206364
List a possible caller functions:

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>  

I know it's incomplete but that's all that is displayed.

David

On the router (I’m assuming is the mesh root) is there an auto select option that will I think reconfigure the mesh if a node goes down? I had instability problems and that was the cause - turn it off (might need to reset mesh unfortunately but try without).

I'm sure there are many people who'll disagree with what I'm going to say - that's fine - if it works for you, etc...

Mesh is an invention for the masses - it makes you think you have a great wi-fi signal but because of the way it sets every AP to the same channel and then (for most home setups) requires use of the same wifi to do the backhaul between the devices it can cause more trouble and worse performance than it fixes.

That said then - (and this will be much better if the AP is hard-wired to the router - if not it adds another level of complexity as it'll require WDS configuration) - turn off mesh and just configure the router and the AP to the same SSID details but on different channels i.e.

2927 - 2.4GHz SSID - 20MHz Bandwidth - Channel 1
906 - 2.4GHz SSID - 20MHz Bandwidth - Channel 6

2927 - 5GHz SSID - 80MHz Bandwidth - Channel 36
906 - 5GHz SSID - 80MHz Bandwidth - Channel 52

amadeus wrote:

On the router (I’m assuming is the mesh root) is there an auto select option that will I think reconfigure the mesh if a node goes down? I had instability problems and that was the cause - turn it off (might need to reset mesh unfortunately but try without).

 

There is a tick box "Auto reselect" which was ticked. I've unticked it to see what happens.

ianfretwell wrote:

That said then - (and this will be much better if the AP is hard-wired to the router - if not it adds another level of complexity as it'll require WDS configuration) - turn off mesh and just configure the router and the AP to the same SSID details but on different channels i.e.

2927 - 2.4GHz SSID - 20MHz Bandwidth - Channel 1
906 - 2.4GHz SSID - 20MHz Bandwidth - Channel 6

2927 - 5GHz SSID - 80MHz Bandwidth - Channel 36
906 - 5GHz SSID - 80MHz Bandwidth - Channel 52

 

Hmmm, interesting suggestion.

During the six months I've been struggling with this I did try ditching the mesh and connecting as a simple AP. I had to use WDS as I can't use a hardwire connection, but problems were even worse as connection was then intermittent and eventually the AP906 didn't, or couldn't, connect at all. Reloading the firmware didn't cure the problem so I went back to to mesh mode. Thanks for your suggestion - it's certainly worth a try.

Yep that’s the one.
Sorry I was a little vague - I’m not in the same country as my hardware. Just realised I could have looked in the online manual but looks like you’ve got what I meant.
Be interesting to hear how you get on.