I visit a store regularly and every time to try to reference something on my phone in that store, I get UI crashes. The phone works fine everywhere else. Its a Oneplus9 running a custom rom.
Two questions:
- What could cause this? Is some sort of interference in the store crashing things? Is the bright light causing the luminosity sensor to overwhelm. Is the store trying to mess with or track my phone in some way and all my modifications, privacy configurations, etc. are choosing to crash instead of allow it?
- Do you have any ideas about how I can figure out what is causing it? Spectrum analysis with a flipper zero or something similar, logs of some kind on the phone, process of elimination? Links are appreciated if it requires advanced nerd cred (I’m probably intermediate with Linux, Android and tech in general, except networking where my knowledge is mediocre bit growing).
I am beyond curious what is going on because it is so weird that it works perfectly everywhere, but the UI keeps rebooting in this one store.
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It sounds to me like perhaps the store has bluetooth beacons in place. It’s a fairly under-utilized piece of tech, so there’s a strong likelihood that your custom ROM doesn’t support it properly. It’s mostly just used for customer tracking, anyway, so the devs of your ROM may have either ignored the feature or deliberately disabled it in some way.
This article talks about what these sorts of beacons in retail stores are used for: https://www.itransition.com/retail/beacons
You mentioned scanning with a Flipper Zero; I’d suggest scanning to see what sort of BLE devices show up in the store.
I think this is the most likely theory yet. I don’t install loyalty apps, but if my phone gets the signal and tries to access something that isn’t there because the devs ripped it out that could explain the instability. It would also make me like the devs more as I don’t want to relieve advertising or be tracked. :-)
Let me see what I can figure out.
try entering with all communications turned off (bluetooth, location, wifi, nfc, flight mode on)
do you have wireless charging?
maybe it’s anti-theft tag detectors near the door.
The last time it happened, I turned off WiFi and BT as well as doing a reboot and it still happened.
I will go and try turning off cell connectivity and if that works, I’ll cycle through 2g/3g/4g/5g and see if it happens with all of them.
The other possibility, although I doubt it really but it’s worth checking for, is they might have a microwave link in the store for some reason, and your phone just kind of gets overwhelmed by all the unshielded energy.
I have no idea how you would even test for that since I don’t think phones can really receive microwave signals so they have no way to detect them but the energy would still mess with them.
Might tie in with what people were thinking about the wireless charging coils.
You could try and get in one of those RF shielding cases and see if that helps.
They are usually sold because people are concerned about contactless somehow being used to steal their money, but since that doesn’t work unless you unlock your phone it’s a bit of an unfounded concern. The cases do actually block RF, so while they’re a kind of con, they do also work.
- Does your phone automatically join open wifi networks?
- Do you have worse cell signal than usual in this store?
My phone scans for networks, but does not automatically join.
I will check on the cell signal aspect of it. The store is walking distance of my home, but the building materials at the store could deteriorate the signal quality worse than being in a timber frame home.
Thank you for the suggestions.
If it’s just the system UI crashing, it’ll be logged and preserved. See if there’s a way to capture a logcat on-device right after it happens.
Are you connected to a particular wifi network, bluetooth device, etc. when this happens?
Hi, yes, I believe its just the UI, it’s not taking nearly the amount of time as a full reboot. I haven’t had a lot of luck capturing meaningful logs on Android but I’ll read up on what logs I can grab. I seem to remember something like “KMESC kernal this or that” that I had to read when troubleshooting an old tablet, but I’m in a bit over my head which means a lot of reading to learn more about Android.
I am not connected to the WiFi, nor do I have the store’s app installed, my garmin watch is connected, but it is always connected.
Found a very similar report, but I’m on TMobile, not FI: https://support.google.com/fi/thread/98016588/my-supermarket-reboots-my-phone?hl=en
Just fyi, I believe T-Mobile is one of the main networks that Fi uses. So it’s still possibly network related.
Agreed, network is and was my #1 suspicion. My paranoid mind immediately assumed they have some kind of advanced customer profiling that pings your phone to see where you are in the store and build a profile and attach it to your loyalty card if one exists. I recognize that Occam’s Razor doesn’t support this theory, at least not until I rule out a lot of other things.
I will add that it happened both near the pharmacy and in the complete opposite corner of the store. It still happened with WiFi and BT off, even after reboot, so that would leave mobile data (multiple generations), NFC, and wireless charging. I will have to toggle through all of these the next time I go shopping.
Oh wow, me too! In my local grocery store I can only use my phone (particularly Todoist) about five seconds at a time before the UI crashes to the lock screen. I’m on a Pixel 5 with CalyxOS.
I am running CrDroid Android 14 for a Oneplus 9. Just like the other link I found, mine happened at a Albertsons/Safeway grocery store. Someone posted something about Bluetooth beacons above. I’m going to pursue that as it sounds like a reasonable guess.
It might be a geo location thing. The Walmart app will switch modes when I go into a store. If your phone has funky things set up around that, it might break.
Could be root adblock breaking that functionality too.
Definitely running root adblock, but no loyalty apps. I’m curious how that would result in a reboot, but you absolutely pegged the type of user I am. :-)
It’s Java…so…make a call to the ad server to say you’re in the store, that returns none and no one caught the error. Poof…reboot.
I might be making shit up, but that’s my best guess. Turn off ad block before you go next time and see if that’s it.
