Problem with 5GHz Wifi on iPhone 12 Pro

@William - to put the router issue to rest could you assist further please? I have a Huwaei F2000 router that is hardly cutting edge but is modern and should have no issue with an iphone 12 pro. It's been reset (weeks ago). Both the 2.4GHz and 5Ghz networks are enabled. I can share any settings with you that you are interested in. I still use my iphone 8 (like a Touch device) in the home and it has no issue. With the iphone 12 the connection just stops randomly every once in a while - i.e no connection to internet through wifi connection (Can't definitively say at this point if other local devices are accessible e.g. SAN - will try that next time the internet hangs). Generally it's > 24 hours between stalls and I haven't narrowed down the timeframe any better. This should not be happening. And as I just said it's on 14.3. The only way to fix it is to toggle Airplane mode. What router settings are you interested in or any advice on what to try with the router? thanks

@William - fair play for checking that. Yes I found that article on the IPv6 issue and checked it - this has been resolved in my case. And I considered trying to get a newer firmware outside of eir support but also decided against it as I could well brick it!. But I keep coming back to the point that the iPhone 12 pro is the only device i have behaving this way in my home. My partner has an iphone 11 and a new ipad for Xmas. I have an older ipad pro, a macbook retina 13 from 2013 and a work MS Surface Pro. No other device is having a problem. It has to be an issue with the phone - at the very least we can define "issue" as some difference. If apple changed something on the 12 pro then at least we could be told so we can accept there is a new compatibility "challenge". As it stands it's the only device in my home with an issue with my wifi !

I purchased the iPhone 12 Mini, The iPhone 12 Pro and the iPhone 12 Pro Max in December to upgrade the family comms. And every phone is working great on my Netgear Nighthawk® 12-Stream Tri-Band WiFi 6 Router - Speed-test on 5Ghz Spectrum ISP is 395Mbps x 22Mbps. I was never able get that speed on my iPhone XS and my Apple Airport. - I have had to reboot my Nighthawk once due to some quirky comm issues, but all else great!

Besides a h/w upgrade--since you are using only your 5GHz band--it could also be something related to Bluetooth since your music seems to be impacted. BT or BLE may have been defined as a requirement somewhere and both operate on 2.4.Ghz. So it may also be something Apple will have to address on iPhone 12.

What does Bluetooth at 2.4 GHz have to do with Wi-Fi at 5 GHz? Sometimes there can be interference with Wi-Fi (rare, because the 2.4GHz band is very wide, and there is no overlap between the BT and Wi-Fi sub-bands).

I have the same issue on my iPhone 12 Pro Max, it is driving me nuts. Apple know about the issue but so far have failed to address. I have a brilliant strong BT Wi-fi setup, with excellent signal in all the rooms of my property. The phone keeps dropping the signal all the time. I have reset the network connection on the phone and on my Wi-fi and still the same issue. The iPhone is the only device that has this issue with Wi-fi. Apple can you finally address issue?

My router is a Hitron modem/router combo. I know, not great but it's all I can afford at the moment.

I've triple checked that I have WPA2 enabled and I've turned the private addresses off when I switch to the 5ghz wifi band. Same results. Doing a speed test on the speedtest app and fast.com from my iPhone, I am getting dial-up speeds or the entire connection times out.

I have a recurring WiFi problem when my iPhone 12 auto connects with a public WiFi network. For example, my iPhone auto connects to Lowe’s 2.4 WiFi. But I am unable to access the internet when using the Lowe’s APP. I have to turn off WiFi to connect to the internet via cellular data. I haven’t tried to diagnose the problem because I am too busy shopping.

Many Wi-Fi networks require you to first click through a screen agreeing to their terms and conditions for using the network, and most often those screens are not triggered until you first attempt to navigate to a new web site.

This is frustratingly seen most often with hotel Wi-Fi networks but virtually all stores do it too.

"Cellular always overrides Wifi", I've heard some hogwash in my time but that is a belter! If you are connected to Wifi it uses it for data, cellular for calls, if you are not connected to Wifi then cellular will be used for both calls and data!

You are correct; if both cellular and Wi-Fi are enabled the phone will use Wi-Fi instead of cellular data. There are a couple of exceptions:

• If you have Wi-Fi Assist on, and your Wi-Fi connection is slow or weak, it will switch to cellular. But this is a very unusual situation.
• When the phone locks Wi-Fi is turned off after 30 seconds to save energy. Any data use while the phone is locked will be cellular.

Yes it does turn off. The phone is unlocked when you make a call, so Wi-Fi is on. If you want to prove it to yourself:

First, get your phone’s IP address for Wi-Fi by going to Settings/Wi-Fi and tap on the i next to the network name

On a Mac: Open a Terminal window and type:

ping <that IP address you recorded)

Windows: Open a CMD window and type:

ping /t <that IP address you recorded)

Now lock the phone and watch the display in the Terminal/CMD window.

I don't need to prove it, just because a device stops responding to ping doesn't mean wifi is off. An inbound Wifi call wouldn't work if Wifi went off when the phone is locked, unless you sit with your phone unlocked all the time. Also, the iPhone is capable of receiving emails, iMessages when locked, even if there is no cellular connectivity.

OK, then explain why there is a constant stream of complaints from users about their phones using cellular data when locked that goes back 13 years.

I did oversimplify; when the phone receives a notification (which uses the cellular voice side channel) Wi-Fi turns on for a few seconds to process it.

You can believe whatever you want, but the facts are the facts.

It is not a bug. It has worked that way on every iPhone and every version of iOS since June 2007 with the first iPhone. It is a feature to prevent Wi-Fi from draining the battery, because Wi-Fi uses energy continuously when connected to a network whether data are being transferred or not. The way to keep Wi-Fi on when locked is to keep the phone connected to power.