Yesterday, My Zenfone 4 can't get 3G connectivity after update. So i do some research why my zenfone can't get 3G/HSDPA signal, and found some solutions to try if your zenfone can't connect to 3G network.
- Make sure you have data network on your SIMcard
- Dial *#*#4636#*#* choose Phone Information>Set Preferred network type: WCDMA preferred or WCDMA Only
- If it's doesn't work Go to Settings>Mobile Network, Make sure you choose 3G or 2G/3G
- If it Revert back to 2G after you choose 3G, go to DualSim Settings
- Exchange your Preferred SIM card (if Voice Call for SIM 1 change to SIM 2 and if Data service Network for SIM 2 then change to SIM 1)
- Wait for a while, then Revert back again to your desired configuration (Voice call for SIM 1 and Data service Network for SIM 2)
- Go to Settings>Mobile Network, choose 3G and try connect to network