TL;DR: If the Z3C camera doesn’t work after restoring the /data partition from another phone, try deleting the contents of the /data/credmgr directory.
Recently I wanted to restore the TWRP backups from my broken Z3C to a new device. The usual process including TA backup and restore went well, however, after the restore, the rear camera of the new device didn’t work anymore, image just staying black. adb logcat revealed errors related to CredMgrDaemon:
E/CredMgrDaemon( 617): GetCredential() ended. result 5 - CREDMGR_RESULT_SERVICE_ERROR E/ ( 590): Failed to open file 'off'. (No such file or directory) E/GenericSource( 590): Failed to create data source! E/MediaPlayer(13150): error (1, -2147483648) E/MediaPlayer(13150): Attempt to perform seekTo in wrong state: mPlayer=0xaed91e40, mCurrentState=0 E/ ( 590): Failed to open file 'off'. (No such file or directory) E/GenericSource( 590): Failed to create data source! E/MediaPlayer(13150): error (1, -2147483648) E/MediaPlayer(13150): Attempt to perform seekTo in wrong state: mPlayer=0xaed91e60, mCurrentState=0 E/libextended_boot( 590): GetCredential() ended. result 5 - CREDMGR_RESULT_SERVICE_ERROR E/libextended_boot( 590): CredMgr_GetCredential() ended. result 5 - CREDMGR_RESULT_SERVICE_ERROR E/CredMgrDaemon( 617): GetCredential() ended. result 5 - CREDMGR_RESULT_SERVICE_ERROR E/libextended_boot( 590): GetCredential() ended. result 5 - CREDMGR_RESULT_SERVICE_ERROR E/libextended_boot( 590): CredMgr_GetCredential() ended. result 5 - CREDMGR_RESULT_SERVICE_ERROR E/CredMgrDaemon( 617): GetCredential() ended. result 5 - CREDMGR_RESULT_SERVICE_ERROR
The solution was to delete the contents of /data/credmgr. After a reboot the camera was working again.
See:
[1] post on XDA
[2] more info