Oppo How to Set default SIM card for mobile data
Oppo 9In addition to calls, a standard SIM card for mobile data can also be changed and the device will only use the specified SIM card for mobile data.
Note: After changing the default SIM card, the device will search for a network again.
Android 10 (ColorOS 7.0)





- Open the Settings
- Tap on SIM card & mobile data
- Tap on Mobile data
- Choose between SIM1 and SIM2
- Confirm with Switch