Troubleshooting Call and Text Issues on GrapheneOS (Carrier Overrides)
Background Context
The Cape app is designed to automatically apply unique carrier settings to ensure your device connects properly to our network. However, due to the privacy and security architecture of GrapheneOS, the operating system can sometimes override or drop these settings—especially when switching between different user profiles. This guide will help you manually lock in the correct carrier settings to ensure your service remains stable.
Scenario 1: No Service / Unable to Make Calls or Send Texts
If you are using GrapheneOS and suddenly experience "No Service," or an inability to make calls and send texts, your device may have dropped its VoLTE connection.
The Cape network requires VoLTE. If VoLTE becomes disabled, your phone will lose its IMS connection. Without an IMS connection, calls and SMS will not work. You can fix this permanently by forcing VoLTE on via Carrier Settings Overrides.
⚠️ Important Profile Requirements:
- You must perform these steps from your Owner Profile.
- The Cape app must be installed on the Owner Profile, as only the Owner Profile has permission to manage and control the eSIM.
- IMSI rotation is only supported in the Owner Profile. Due to security constraints around carrier configurations within Graphene Secondary Profiles, if an IMSI rotation occurs while in a secondary profile, you may lose service until you switch back to the Owner Profile.
Step-by-Step Instructions
Step 1: Ensure VoLTE is Enabled
- From your Owner Profile, open the Settings app.
- Go to Network & internet → SIMs and select your active Cape SIM.
- Scroll down and verify that the VoLTE toggle is turned ON.
Step 2: Access Carrier Settings Overrides
- On the same SIM settings page, scroll down and tap on Carrier settings overrides.
Step 3: Force VoLTE Availability
- Tap on VoLTE / Vo4G availability and change the selection to Forced available.
Step 4: Force 5G Capabilities
- Next, tap on 5G capabilities and change the selection to Force NSA and SA.
Step 5: Enable Overrides
- Confirm your settings match the highlighted boxes, then toggle Enable overrides to ON at the top of the screen.
Step 6: Toggle Roaming (If Needed)
- If you still do not have a connection, tap the back arrow to return to your main SIM settings page. Ensure that Roaming is toggled ON.
What to Expect Next
By forcing these settings, your device is now locked to using VoLTE networks, ensuring your IMS connection remains stable for calls and SMS.
Multi-Profile Usage: With the overrides active, you should now be able to safely use your secondary profiles without losing network connectivity, provided the Cape app remains installed and active on the Owner Profile.
Scenario 2: Outbound Calls Failing (SMS Still Works)
If you are able to send and receive SMS messages but outbound calls are failing, the ImsService app on your device may have lost its network permissions. GrapheneOS's strict privacy controls can sometimes revoke system app permissions, preventing the ImsService from establishing the connection required to place calls.
⚠️ Note: This step requires enabling the display of system apps within the Permission Manager. Take care not to modify permissions for any other system apps while in this menu.
Step-by-Step Instructions
Step 1: Open Permission Manager
- From your Owner Profile, open the Settings app.
- Navigate to Security & Privacy → Privacy Controls → Permission Manager.
Step 2: Access Network Permissions
- Tap on Network from the list of permission categories.
Step 3: Show System Apps
- Tap the three-dot menu in the top right corner and select Show System to make system-level apps visible.
Step 4: Locate ImsService
- Scroll through the list and tap on ImsService.
Step 5: Restore Network Access
- Under the Network permission, change the setting to Not Allowed, then restart your device.
- After restarting, return to the same ImsService → Network permission screen and change the setting to Allow, then restart your device once more.
What to Expect Next
Cycling the network permission and restarting between each change helps ensure the ImsService app fully resets its connection state. Once complete, your device should be able to establish the IMS connection required for outbound calls. If calls are still failing after completing these steps, revisit Scenario 1 to confirm your VoLTE and carrier override settings are correctly configured.