My phone is a stock Nexus 4 from Google with the 5.0.1 Lollipop image from Google.

I've mistakenly hit "reset APN settings". Instead of resetting them to defaults, it wiped them off and grayed out the "add access point" button. I don't know what to do to gain access to this back.

I've tried launching the "Settings" activity from the terminal with root access (using the "su" command), see this answer, but the "Settings" activity crashes right after its launch.

What can I do? There seems to be a user permission problem. I'm using the only user account configured on this phone, besides the "guest" user.

  • Would factory resetting the phone be a viable option for you (losing all data in the process)?
    – Chahk
    Dec 31 '14 at 16:48
  • Rather not. And it wouldn't guarantee this not happening again anyway, because the phone was freshly reinstalled when I lost this permission.
    – Cutter
    Jan 1 '15 at 13:18

I've found the problem: I had bad permissions on various MMS-related files that I've copied from a backup, especially inside data/data/com.android.providers.telephony/databases/.

Files inside data/data/com.android.providers.telephony/ have to belong to the radio group and be owned by the radio user. CHMOD has to be at least 761.

  • So how did you fix the permissions problem ?
    – lnxnubie
    May 6 '15 at 10:16
  • IIRC files inside data/data/com.android.providers.telephony/ have to belong to the radio group.
    – Cutter
    May 6 '15 at 10:28
  • 1
    This didn't work for me. When I changed permissions in the telephony directory to 660 from 751 and rebooted I got non-stop com.android. phone error messages
    – raphael
    Jun 21 '15 at 15:54
  • Try 761, don't downgrade any permission
    – Cutter
    Jun 22 '15 at 20:14
  • I encountered a different solution, as this didn't work for me. I wrote it up on this related post
    – Hendy
    Sep 22 '15 at 14:44

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