@nickbg321 I'm seeing something very similar with my units, and it's the same even with the beta firmware mentioned above.

I've had no issues with the units in the past, but they're completely unstable now. I've been pricing up swapping them out for the Amazon Eero units (but annoyingly their satellite units have no Ethernet ports).

Basically the satellite unit will occasionally drop the connection, and I've got mine on a wired backhaul too. It seems that I can trigger it to drop by performing a speedtest on a device that's connected to it. So if I go downstairs, wait for it to switch over, then start a speedtest it'll start the test and then the light will go yellow and it'll drop out.

I'd really like to downgrade the firmware to a previous version so that I can keep the units, but unforunately I don't think that's going to be possible so looks like I'll have to return them.

@Jordan1996 I've also thought about downgrading from 1.5 to 1.4 but that doesn't seem to be possible from what I know and unfortunately I'm way past the return period on mine.

1.5.0 firmware has been hot garbage for me so far. With both my wife and I working from home due to Covid these issues have been especially frustrating. Don't think I'm buying another TP-Link product again.

 @TP-Link I haven't really paid attention to the light color but I will try to the next time it happens.

@TP-Link Hi, thanks for the reply. Apologies for hijacking this thread, but I believe it could be the same issue that we're both facing.

I've tried a few different configurations to see if anything made a difference, but it happens in all of the following setups:

Modem -> Main Deco (Router Mode) -> Netgear Switch -> Wired 2nd M4

ISP Router -> Main Deco (AP Mode) -> Netgear Switch -> Wired 2nd M4

ISP Router -> Main Deco (AP Mode) -> Wired 2nd M4

ISP Router -> Main Deco (AP Mode) / Wired 2nd M4

In all scenarios the 3rd M4 is connected wirelessly via the Main Deco.

I have tried moving the roles of the Deco's around the house, but the issue I'm seeing is that no matter which device I have downstairs (on the Ethernet cable), the issue persists. Even when disconnecting the Ethernet cable on this device I see the same issue occurring when utilising the wireless backhaul.

Interestingly, when testing this morning this issue seems to be device specific. If I connect to the downstairs M4 and perform a speed test using my Surface Pro I'm able to complete the speed test at 220Mbps download and 20Mbps upload (the package maximum speed). However if I perform the speed test using my iPhone 12, it'll get to around 150Mbps and this seems to force the Deco to reboot.

The Ethernet cable is around 35M in length and has been tested using a Fluke cable tester, so there's no issues with the cabling - plus the same issue occurs when the wireless backhaul is in operation too which would rule that out.

Confusingly it's only affecting whichever device is downstairs, no matter which device that is. And when the devices are upstairs (either in router mode or wireless extender mode) and I perform the same tests they're fine.

I've captured a video this morning to show the status of the LED's whilst this is happening. A few seconds after the speed test starts the LED will go yellow, then eventually it'll flash red before going white after about 2 minutes.

Just a note to add that the downstairs device does randomly reboot during the day too which is the main issue - the speed testing just seems like a quick way to see if the issue is resolved.

I'm planning on leaving a ping test running during the day to capture the drops and latency spikes that I might not even be aware of, so once I have the results from that I'll pass them onto you. I'll do this before downgrading the firmware to see if that resolves the issues.

Link to video

Just to add to something I noticed which may be useful for debugging the problem:

Wireless speed decrease seems to mainly affect download. I get around 100-120mbps up, which is the same as when I'm connected to the main unit.

Also my units use wireless backhaul.

@TP-Link I am facing the exact issue after upgrading to 1.5.0. Kindly provide a new workable firmware or at least provide the 1.4.3 firmware for a temporary workaround.