POCO F7, WiFi stays “connected” but WAN dies every few minutes. Not IPv6, not my router, not my MAC and Xiaomi has had it “under analysis” for 10 months.

TL;DR

POCO F7 (Snapdragon 8s Gen 4) connects to WiFi at full speed (866 Mbps, RSSI 37 dBm) and LAN traffic works, but internet (WAN) dies after a few minutes(in my testing). From the very first minute the network was flagged as "no internet", dumpsys showed the classic self sustaining validation loop (network fails validation, BSSID blacklisted, no default route, validation fails again). I then disabled captive portal validation via captive_portal_mode 0 and this is the interesting part: the network immediately became VALIDATED with correct routing, yet WAN traffic still died after ~5 minutes anyway. So the validation loop is a symptom, not the cause. I ruled out IPv6, my router, MAC randomization and DNS: the remaining common denominator appears to be the phone's networking stack (Qualcomm FastConnect 7800). Xiaomi acknowledged this bug on 27 Oct 2025 and it is still "under analysis" 10 months later, with no fix in any weekly report.

1. Setup

POCO F7 (global, released 2025), HyperOS 3 OS3.0.301.0.WOLEUXM
SoC: Snapdragon 8s Gen 4 (SM8735), WiFi: Qualcomm FastConnect 7800 (WCN7850), WiFi 7/6E/6
Network topology: the phone connects to a TP Link Archer C6 (firmware c80_1.14.0) running in Access Point mode, which is behind a Huawei EG8145V5 (the ISP router/gateway)
IPv6 disabled: the whole network is IPv4 only
Bought end of May 2026, worked flawlessly for ~2 months, issue appeared late July 2026
All other devices on the same network work 100% of the time

1. Diagnostic timeline (what I actually did)

WiFi shows connected (866 Mbps) but pages/apps fail: ping 8.8.8.8 = 100% loss, curl returns HTTP code 000.
LAN is fine while WAN is dead: ping to gateway = 0% loss / ~5 ms, router web UI = HTTP 200.
From the very beginning the network was marked "no internet": dumpsys connectivity shows WiFi NOT VALIDATED (LTE VALIDATED). dumpsys wifi shows repeated addToBlocklist … REASON_NETWORK_VALIDATION_FAILURE with block times growing 5 min up to 5 h. No default route in ip route. DNS resolves fine via the router. Result: a self sustaining loop, where a network once flagged "no internet" keeps failing validation and keeps itself on the blacklist.
Suspected router side blocking: checked both routers: the TP Link Archer C6 (the AP the phone connects to) and the Huawei EG8145V5 (gateway). No blocked devices, no quarantine, no MAC filter, no parental controls on either.
Tested both randomized AND fixed (device) MAC: same failure on both.
Then disabled captive portal validation entirely (see section 3): this is where it gets interesting.

1. The key experiment

adb shell settings put global captive_portal_mode 0

After this, the network is instantly treated as VALIDATED: ip rule shows the correct lookup 1025, the default route exists, connectivitycheck.gstatic.com returns 204, ping works. For about 5 minutes. Then WAN dies again (curl = 000) while the connection is still up, still VALIDATED, and routing is still correct.

So to be precise about the states:

Before the experiment: network NOT VALIDATED, no default route, blacklist loop, no internet.
After the experiment: network VALIDATED, routing correct, still no internet after a few minutes.
Same symptom, two completely different Android level states. That alone strongly suggests the validation loop is a symptom, not the root cause: the phone's own network module/radio stops forwarding WAN packets even when every Android level check says "healthy".

Theories tested
Captive-portal validation loop | Excluded (captive_portal_mode 0 didn't change the outcome)
Router / MAC filter | Excluded (no blocks on the Archer C6 AP or the Huawei EG8145V5 gateway; fails on random AND fixed MAC)
IPv6 bug ( [#429703129](https://issuetracker.google.com/issues/429703129) ) | Excluded (IPv4-only network)
DNS | Excluded (resolves; fails on raw IP)
Weak signal | Excluded (-37 dBm, 866 Mbps link)

What helps, temporarily: toggling WiFi off/on; "Reset WiFi, mobile networks & Bluetooth" (works 1–2 days, or until the first reconnect). Nothing permanent. The issue persists on the current HyperOS 3 build (i.e. after the Android 16 update).

1. It's not just the F7: map of the same radios.

POCO F7's WiFi is the Qualcomm FastConnect 7800. The same radio (or its successor 7900) sits in a lot of recent phones, and several have reported suspiciously similar "connected but broken" symptoms that were usually blamed on the router or IPv6:

POCO F8 Pro (SD 8 Gen 3 with FastConnect 7800): XDA post shows WiFi frozen 5 to 10 seconds on every screen wake, "all other devices work fine, strictly isolated to the Poco F8 Pro". The user's fix was disabling MLO on the router, which masks, but doesn't explain, why only this phone breaks. [XDA thread](https://xdaforums.com/t/bug-poco-f8-pro-hyperos-5-to-10s-wi-fi-delay-freeze-upon-screen-wake-mating-with-xiaomi-be7000.4780116/)
POCO F8 Ultra (SD 8 Elite with FastConnect 7900): Reddit reports WiFi disconnects every few minutes, users blame IPv6; disabling mobile data "stops it" [Reddit thread](https://www.reddit.com/r/PocoPhones/comments/1sivxfx/poco\_f8\_ultra\_have\_you\_noticed\_any\_issues/)
Xiaomi 15 (FastConnect 7900): officially listed with a "WiFi not working" bug in a weekly bug report. [Gizmochina article](https://www.gizmochina.com/2025/10/29/xiaomi-hyperos-weekly-bug-report-wifi-charging-fixes/)
Same FastConnect 7800 family, other OEMs: Redmi Turbo 4 Pro (China twin of the F7), Xiaomi Civi 5 Pro / 15 Civi, iQOO Z9 Turbo, OnePlus Nord 4, Motorola Edge 50 Ultra, plus SD 8 Gen 3 flagships (Xiaomi 14, OnePlus 12, Galaxy S24…).
My hypothesis (not proven): this is a firmware/driver defect in the Qualcomm WiFi radio or its integration in HyperOS, not IPv6 and not home networking. If you own one of these phones, your report helps confirm or kill this.

1. What Xiaomi says and how long this has been ignored

Vol 208 (25 Jul 2025): POCO F7 already listed "Slow WiFi speeds (especially on 5GHz)", under investigation. [Xiaomi Community Vol-208](https://new.c.mi.com/global/post/1561930)
Vol 219 (27 Oct 2025): POCO F7: "WiFi connected but not working, disconnects automatically". Status: "under analysis", with a workaround that doesn't appear to address the underlying issue ("reconnect, or grant Notification permission"). [Xiaomi Community Vol-219](https://new.c.mi.com/global/post/1954072) [Gizmochina summary](https://www.gizmochina.com/2025/10/29/xiaomi-hyperos-weekly-bug-report-wifi-charging-fixes/)

Every weekly report since (Nov 2025 to Jul 2026): the F7 WiFi bug appears nowhere: not in "fixed", not even relisted as "under analysis".
Interestingly, multiple community reports describe the same temporary pattern I observed: resetting WiFi/network settings restores connectivity only for a limited time before the issue returns. While this doesn't prove the same root cause, it suggests my case may not be an isolated hardware failure.

That's 10 months (over a year if you count from Vol 208) with the status stuck at "under analysis" and no fix shipped

1. Please help me collect data (even quick replies help!)

If you have a POCO F7 / F7 Pro / F7 Ultra, F8 series, Xiaomi 15 series, Redmi Turbo 4 Pro, or any other phone with Snapdragon 8s Gen 4 / 8 Gen 3 / 8 Elite, and you've noticed weird WiFi behavior, please share your experience below!

Even if you aren't tech-savvy, just answering a few quick questions helps a lot:
– Phone model & HyperOS version
– What are your exact symptoms?
– What fixes it and how long does it last?
– When did it start? (Out of the box, or after a specific update?)

**(Optional for Power Users)**

If you're comfortable using ADB, I'd really appreciate one extra test. It helps determine whether the problem is caused by Android marking the network as invalid, or whether Internet traffic dies even while Android still considers the WiFi connection healthy.

Disable captive-portal validation:

adb shell settings put global captive_portal_mode 0

Then use the phone normally until the issue happens again. As soon as the Internet stops working, check:

adb shell dumpsys connectivity

and, if available:

adb shell ping 8.8.8.8

If your build includes curl, you can also run:

adb shell curl -s -o /dev/null -w "%{http_code}" http://connectivitycheck.gstatic.com/generate_204

Please let me know:
– Does WiFi show **VALIDATED** or **NOT VALIDATED**?
– Does `ping 8.8.8.8` still work, or is it 100% packet loss?
– Does toggling WiFi restore Internet immediately?

If the network remains **VALIDATED** while Internet traffic is already dead, that's particularly interesting because it suggests the validation system isn't the root cause.

1. Service note

I've filed this as a warranty claim; I'm sharing this so anyone Googling the symptom finds the full technical picture instead of another "have you tried restarting your router". Happy to post a follow-up if/when a fix lands.