Iโm writing to report a technical problem with latest US Samsung Galaxy S25 Ultra cellphone (and possibly others).
Now running Android 16 and One UI 8 (released by Samsung & installed late Sept 2025) and Oct 2025 update patch.
Hereโs a normal working WiFi info screen of the S25U using the WiFiMan Android app from Ubiquiti. You can see my โWestOfTheMoonโ SSID WiFi , broadcasting the same SSID on 2.4G, 5G & 6G fixed-freqs, with its connection to the closer Access Point and the S25U connected at WiFi7 on the 6G band, WPA3-SAE. You can also see the weaker (relative to the S25Uโs location) Ubiquiti AP across the house, broadcasting on the same โWestOfTheMoonโ SSID on its three fixed freqs (2.4G, 5G, 6G). The two Ubiquiti APs operate as a mesh, coordinating handoff over their 2.4G wired Ethernet links (connected to the Internet thru a router and 2G cable modem).
Assuming Iโm at the end of the house based on the information captured below, weโll call
the closer AP โAโ, broadcasting on 2.4G Chan1, 5G Chan149, 6G Chan69 [all fixed freqs on the Ubiquiti]
the farther AP โBโ, broadcasting on 2.4G Chan11, 5G Chan36, 6G Chan5 [all fixed freqs on the Ubiquiti]
With Ubiquiti WiFiMan app, on Samsung S25U = good case, connected on 6G of stronger AP
And a simple stock Samsung WiFi status page on Samsung S25U = good case, shows 6G-connected
Not as good WiFi telemetry as seen with the WiFiMan app, but Samsung should believe thisโฆ
But below we see the problem/failure when it happens, with the Samsung S25U now only seeing the 2.4G & 5G bands of the nearer AP โAโ, but *not* the 6G band Chan69 that the closer AP is broadcasting on the same SSID. So it connects to the strongest & fastest band, 5G, it still sees from that closer/stronger AP. This never โrecoversโ on its own, until the phone is moved out & in (and out & inโฆ) range of the AP(s).
With WiFiMan app, on Samsung S25U = bad case
WiFiAnalyzer app, all bands displayed (weaker ones off-screen), on Samsung S25U = bad case.
6G band on the closer Ubiquiti not seen for the WestOfTheMoon SSID.
WiFiAnalyzer app, only 6G bands displayed, on Samsung S25U = bad case.
6G band on the closer Ubiquiti not seen for the WestOfTheMoon SSID but is seen for others.
S25U has decided to connect to Ch149 5G
The important things to note is that the Samsung S25U phone *is* receiving 6G wireless signals (e.g. EastOfTheSun SSID โ which is broadcasting 2.4G, 5G & 6) and WeUniFi6G SSID (only broadcasting 6G) per from multiple APs per multiple Android apps. But itโs *ignoring* (no longer seeing/reporting/connecting-to) the 6G signal that the Ubiquiti is broadcasting over the WestOfTheMoon SSID (+5G & 2.4G). It only sees 5G and, although not shown above, 2.4G, but is not reporting or connecting-to the 6G signal on that same SSID.
You can see the โstrong enoughโ (to see, but not connect to) 6G Chan5 from the far โBโ weaker AP, with the WiFiMan app showing a weak outline in the area where the much closer & stronger 6G Chan69 *should* be received on the S25U but is not reported. That may be telling us something โ is the S25U seeing โsomethingโ at that 6G freq. but isnโt able to connect to it (WPA3, link).
With WiFiMan app, on Samsung S25U = bad case
So onto the finger-pointing that Samsung will be doing โ The obvious question is, is the Ubiquiti AP still broadcasting, or not, on the 6GHz Chan69 at this moment? That is, is the problem at the Ubiquiti AP end or the Samsung Galaxy S25U end?
Fortunately we have an easy way to determine that using my wifeโs Samsung Galaxy S24 Ultra (also running Android16 & One UI 8, also with the Android apps), sitting next to the S25U.
The following screenshot of the WiFiMan app on the S24U shows it connected, at the same moment and location as the S25U thatโs *not* connected, to the *same* โWestofTheMoonโ SSID on the 6G Chan69 frequency, with all three freqs being broadcast by both โAโ & โBโ APs -- even as the S25U above is not connected on that 6G Chan69 freq nor even showing itโs being broadcast & received. But clearly the 6G freq is still broadcast, at a good -49dBm strength as seen by the S24U.
With WiFiMan app, on wifeโs Samsung S24U = good
WiFiAnalyzer app, all bands, on Samsung S24U == 6G on WestOfTheMoon.
The S24U can see (and is connected) to the 6G freq on the WestOfTheMoon SSID.
and
WiFiAnalyzer app channel graph, only 6G bands, on Samsung S24U.
Hard to read with SSID-text overlap, but you can see the SSIDs of all 6G broadcasters
This data on the 24U phone was taken at same moment the Samsung S25U failed to report (let alone connect) on the 6GHz Chan69. The two phones are sitting about 5ft apart, in the same room with line-of-sight to the closer Ubiquiti XG AP on the ceiling.
Iโve collected data using several Android WiFi apps proving what is being broadcast and/or (not) received on the various phones. I didnโt bother including all here since the Ubiquiti WiFiMan app, WiFiAnalyzer app & simple Samsung WiFi screen show the issue cleanly & clearly.
Proven: The Samsung S25U (at least) sometimes disregards (failing to see/report, let alone connect) a strong 6G signal when the same SSID is being broadcast simultaneously on the 2.4G, 5G & 6G bands. It instead connects on a slower (5G in this case) band even though the 6G signal is present and nearly as strong and doesnโt claim to even see the 6G broadcast on that same SSID.
I donโt know if the S24U also has the problem since Iโm not using that phone often (my non-technical wife is) and have only used it as WiFi checker when my S25U phone exhibits this problem. At those moments, the S24U has no problem connecting to the 6G band of the WestOfTheMoon SSID broadcasting 2.4G/5G/6G.
I donโt have a clear & clean procedure for causing the S25U to lose 6G โ e.g. does it sometimes happen when the S25U is moved from near AP โBโ to AP โAโ or vice versa? Does it sometimes happen when the S25U is brought into the house from the outside and initially connects to the AP โAโ? etc. Is it equally likely to failure with either/both APs or 6G channels? Does it sometimes happen when WiFi reception on the S25U phone is disabled then reenabled or the phone is rebooted? I can definitively tell you that it doesnโt *always/consistently* happen based on those things since Iโve intentionally replicated each many times. And that it does happen randomly & mysteriously as the S25U is moved around my house.
I fully realize what Samsung is going to do with this information โ ignore, bury or deny it, with typical finger pointing == โit must be your Ubiquiti APs or the Wifi signals in your houseโ, โit must be the Android apps youโre using to view the WiFi signalsโ.
But no, thatโs not supported by the evidence and in fact contradicts it. Iโve now fully replicated *and* documented, with multiple Android apps and native Samsung info, this 6G multi-freq same-SSID failure with the S25U while showing with the S24U that that 6G signal on the same multi-freq SSID *is* being broadcast (i.e. itโs not a Ubiquiti problem) and connected-to/received by the S24U (the same 6G signal works with another Samsung phone, at least some of the time).
So Iโll give Samsung a little time to investigate this and report back to me, asking more questions if needed and ideally confirming the behavior. And hopefully reporting that a software/firmware update is in the works. And that the problem has been corrected for the S26 etc.
