I am using rooted but stock Nexus 5 D820 with service provider Airtel in India. When I occasionally glanced my phone it said that the SIM is not detected.
I soon discovered by various means that my phone is accepting the SIM while there is no problem with the SIM and the network. I isolated these by trying other working SIMs in my phone and my SIM works on other phones. Also switching from 4g->3g->2g also tried.
IMEI is okay and not changed. EFS folders are backed up. This issue did not happen during any tweaking operation, rather should have happened after few minutes after receiving the call.
Service center staff said they had to replace the entire board.
Question: If you are still reading, though my SIM is not detected, the phone can still search network providers when I choose
manual option for network selection. When I choose my service provider manually it fails to register.
My question is if the hardware or the SIM has gone defective, how it can scan for available networks but not register with my network?