Deco M5 after firmware 1.8.5 update, no IP on Guest Network

I have a mesh network of 6x Deco M5 all connected through ethernet on unmanaged gigabit switches. I run an AirBnb, with a guest network for guests and TVs.
Yesterday I updated the Deco firmware to 1.8.5 Build 20250612 Rel. 44225 on all Decos. Soon afterwards, my guests reported that the couldn't connect and that the smart TVs weren't working. If try connecting to the guest network, I get IP address allocation failure. Everything works fine on the main network. I only have dumb switches and have not made any other changes to the network in several years. As such, this seems to be a new bug specific to the latest firmware release. I have rebooted everything several times and even swapped out main Deco, but to no avail.
I have temporarily given my guests access to my main WiFi network, but this far from ideal as this has all my smart devices and security equipment on it.
Hoping for a veey quick bug fix release
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@David-TP Update - found a workaround. I started an IOT network as a test and it worked fine, so I renamed and disabled the guest network and set the IOT network to the previous guest network SSID and password. That worked perfectly and guest devices automatically reconnected.
Now it's not urgent so will wait for next firmware release to re-instate guest network.
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Hi, thank you very much for the update.
It is quite like the post here: Reported Issue and Workaround: Guest Network works only on Main Deco
Have you tested whether the devices could connect to the Guest network of the main Deco M5?
I don't think it is related to the 1.8.5 firmware upgrade.
I'll forward your case to the senior engineer for further analysis.
Please check whether you can receive my email later.
Best regards.
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@David-TP Update - found a workaround. I started an IOT network as a test and it worked fine, so I renamed and disabled the guest network and set the IOT network to the previous guest network SSID and password. That worked perfectly and guest devices automatically reconnected.
Now it's not urgent so will wait for next firmware release to re-instate guest network.
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Hi all,
I started the 1.8.5 deco firmware update and looks like something went wrong. Looks like the firmware wasn't installed. Now everytime I open the app I receive a message to update my deco to manage my network BUT the button to update is not active. I switched off my decos M5 and even reinstalled the app but no change. Is anyone able to help?
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Thanks for the update.
Can you record a video clip for me?
(If the Video is too large, you can post it as a YouTube private link)
Have you tried to update via the web UI:
https://www.tp-link.com/en/support/faq/1599/ (method 2)
Wait for your reply.
Best regards.
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@David-TP hi David, not allowing me to upload the video here. I tried updating the firmware on the app, the process started and not sure what happened. Now when I open the app, always ask me to update the firmware but button is blue without text and not clickab
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Great! And there was a similar post today about the 1.8.5 firmware push notice.
https://community.tp-link.com/en/home/forum/topic/837842
When you mentioned, "the button to update is not active", is it like this picture:
Wait for your reply.
Best regards.
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@eppy
I have the same situation, but only if the remote end deco is on a wired backbone vs wifi backbone.
is any of your Deco M5 on a wired backbone?
The main network is working on the remote Deco M5 even though it is a wired backbone.
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@HNza Indeed all 6 M5 Decos are connected on an ethernet backbone. However, as I mentioned earlier I have now disabled the guest network and created a new IOT network with the same SSID and password - that is a good workaround for now. I live in Italy in a villa with meter thick stone walls, so a WiFi backbone has barely any signal between APs and is too slow to support streaming
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I have the same situation, with two M5 connected via wired backbone.
The workaround suggested by @eppy worked for me as well:
1. rename the Guest network
2. disable the Guest network
3. enable an IoT network, give it the same SSID and password as the initial Guest network
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Helpful: 5
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Replies: 22
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