The basic situation is this:
- Phone tries to connect to my parents' WiFi, fails
- The WiFi then drops shortly, no other devices can connect to it
- A laptop connected via ethernet to the router can still access the internet
- Only way to resolve WiFi issue is to restart the router.
- Connecting to another WiFi (i.e. my dad's phone's hotspot) also fails, no connection can be made
I have tried the following things:
On my phone:
- Factory reset (running the latest pre-Oreo OxygenOS, OnePlus 5)
- Restore an old backup from a month ago, full NANDROID via TWRP.
- Wipe everything, again.
- The above, with various combinations of...
- Locked or unlocked bootloader
- Stock recovery or TWRP
- Flashing the latest LineageOS nightly.
None of the above attempts changed anything. Even during the initial setup process, trying to connect to the WiFi fails (and kills the WiFi for everyone else)
On the router
- Factory reset
- Changing from DHCP to static IP (some forum posts suggest duplicate IP in this scenario)
- Changing the address range of DHCP from .100 - .199 to .10 - .99 to ensure all devices get new IPs
Conclusion
I have googled all the things. I have tried everything I can think of. I have no idea what else to try.
On top of this, the mobile network at my parents' place is so bad my phone basically has no internet connectivity.
This has been going on for 3 days now.
I am sad.