Deco XE75 port 1 randomly stopped working
I am reaching out regarding a serious issue with my Deco XE75 3-pack (EU hardware version 1.0).
Since recently updating to firmware version 1.4.3 Build 20240926 Rel. 38336 (which appears to have been silently pushed, as it is not listed on your official EU support site), all LAN ports on all three Deco units are failing to properly negotiate gigabit speeds.
Issue summary:
Port 1 often either fails to link or connects at 10 Mbps with very slow negotiation times (~20–30 seconds).
Ports 2 and 3 consistently link at 100 Mbps, also with long negotiation delays when used with a gigabit-capable desktop.
The Wi-Fi speeds remain unaffected and stable at expected rates.
What I have tested:
Factory reset of the Deco mesh network.
Swapping Deco units between rooms and roles.
Multiple Cat5e and Cat6 cables confirmed good.
Testing with both a gigabit-capable desktop and a laptop with a 100 Mbps NIC:
Laptop connects instantly at 100 Mbps on all Deco ports.
Desktop experiences long delays and fallback speeds on all Deco ports.
Direct connection between desktop and laptop shows instant gigabit negotiation and no delay, confirming the desktop NIC is functioning properly.
Connection between desktop and a spare router shows stable, near-instant negotiation, further confirming the desktop NIC is fine.
The problem clearly lies with the Deco units, and specifically their LAN ports, as they are unable to successfully negotiate gigabit speeds after this firmware update.
Request:
Please confirm if this issue is a known regression in firmware v1.4.3 Build 20240926 for EU V1.0 hardware.
Thank you for your assistance.
Hi, welcome to the community.
The official 1.4.3 could be found here: https://www.tp-link.com/en/support/download/deco-xe75/v1/#Firmware
- Do you still remember the original firmware before 1.4.3?
If it were the 1.4.1, the 1.4.3 could revert to this version directly via the web admin UI.
Have you ever noticed if the Deco APP would report "WAN Speed error" or "Ethernet Connection is slow and please change the cable"
As there are 3*Deco XE75 units, can I have some pictures of the network map on the Deco App, such as:
Wait for your reply.
Best regards.
Good day
I hope you are well.
I don't recall the original software I believe it was 1.4.0, I actually attempted last night to reroll the firmware to 1.4.0.
However, to no avail. There was failed negotiation on port 1 again and if it did negotiate it did it and the link speed of 10/10Mbps.
The configuration of the Decos is as follows.
The bedroom is the main Deco which is connect to the ONT as it is acting as a router, the other 2 Decos are connected wirelessly.
The issue lies between the negotiation of the desktop and the Deco, despite switching out the living room and office Deco it still failed to negotiate the gigabit speed on any of the ports.
I originally thought it was the NIC chip on my desktops motherboard but when testing with an alternative router it negotiated a 1Gb link.
However, the miraculous thing is it is across both the living room deco and office Deco which would suggest the NIC but the tests prove it otherwise.
Kind regards
