Some users notice the problem almost immediately after a carrier update. The phone works normally outdoors, but once inside a house, office, mall, or parking structure, signal strength drops sharply or disappears completely. Calls may fail, mobile data becomes unstable, and the device repeatedly switches between bars, 4G, 5G, or even “No Service.”
If this started right after a carrier settings update or network-side change, the phone itself usually isn’t broken. The behavior typically points to how the device now connects to nearby towers.
Why This Happens
Carrier updates often modify how a phone prioritizes network bands. After an update, the device may prefer newer high-frequency bands or aggressive 5G connections. These signals are faster outdoors but struggle to penetrate walls, concrete, or metal structures.
Previously, the phone may have stayed connected to a stronger low-band LTE signal indoors. After the update, it keeps attempting weaker higher-frequency signals instead, which leads to sudden signal loss inside buildings.
In some cases, the update also resets network calibration, forcing the phone to relearn tower selection behavior.
Step-by-Step Fixes
Reset Network Settings
This is the most effective first step because carrier updates sometimes leave old configuration data behind.
- Open Settings
- Go to General Management or System
- Select Reset
- Tap Reset Network Settings
The phone will restart network connections and reconnect to nearby towers using fresh parameters.
Disable Automatic 5G Selection Temporarily
If indoor signal worsened after the update, forcing LTE often stabilizes reception.
- Open Settings
- Tap Mobile Network
- Select Network Mode
- Choose LTE/4G instead of Auto or 5G
Lower-frequency LTE signals travel through buildings more reliably.
Toggle Airplane Mode for a Clean Reconnect
This forces the phone to renegotiate tower connections.
- Enable Airplane Mode for about 30 seconds
- Turn it off again
Watch signal behavior indoors after reconnecting.
Check Carrier Settings Update Again
Sometimes carriers release quick follow-up patches.
- Go to Settings → About Phone
- Check for Carrier Settings Update
Remove and Reinsert the SIM or Refresh eSIM
A carrier update may require the SIM profile to reinitialize.
- Power off the phone
- Remove the SIM card
- Wait one minute
- Insert it again and power on
Optional Alternative Solution
If indoor coverage remains weak, enable Wi-Fi Calling. This allows calls and texts to route through a stable Wi-Fi connection instead of relying on weakened indoor cellular signals. Most carriers support this feature and it immediately bypasses building signal limitations.
If signal strength returns after switching network modes or resetting settings, the issue was caused by post-update network prioritization rather than hardware failure.