[Nexus 4 Q&A, Help & Troubleshooting] nileshgr:
Since last few days, my phone was behaving erratically wrt battery. Randomly battery used to jump from 93->20 and such. I had a few automated poweroffs too because of that (probably bad battery). But after charging it fully, it started working again, but it started losing cell radio signal randomly.

Now it just doesn't boot (tried even factory image twice, factory reset from fastboot as well as twrp).

When I flash a custom rom (which has adb enabled by default), I get to see this in adb logcat:

E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
W/AudioSystem( 646): AudioPolicyService not published, waiting...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
W/AudioSystem( 646): AudioPolicyService not published, waiting...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
W/AudioSystem( 646): AudioPolicyService not published, waiting...
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
W/AudioSystem( 646): AudioPolicyService not published, waiting...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
W/AudioSystem( 646): AudioPolicyService not published, waiting...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
W/AudioSystem( 646): AudioPolicyService not published, waiting...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
W/AudioSystem( 646): AudioPolicyService not published, waiting...
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
W/AudioSystem( 646): AudioPolicyService not published, waiting...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...
W/AudioSystem( 646): AudioPolicyService not published, waiting...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/kickstart-qcks( 188): Trying to bring MDM9K out of reset
I/ServiceManager( 646): Waiting for service media.audio_policy...
I/ServiceManager( 646): Waiting for service media.audio_policy...
E/kickstart-efsks( 699): File '/dev/efs_hsic_bridge' was not found
E/kickstart-efsks( 699): /dev/efs_hsic_bridge does not exist.
I/ServiceManager( 646): Waiting for service media.audio_policy...

Phone dead?