The operator can manually select the active SIM by configuring a specific SIM as active, either 1 or 2. This configuration makes the selected SIM permanently active.
The active SIM can be manually switched by changing the active-sim setting from 1 to 2 or from 2 to 1.
Changing the active SIM from 1 to 2 or from 2 to 1 is service-affecting. The recovery time after making this change can range from a few seconds to up to a few minutes.
When the system powers up or reboots, it uses the active-sim setting to determine which SIM is the active SIM. If the operator configures the active-sim as 1 but there is no physical SIM in the associated SIM slot, the cellular port remains operationally down. The operator must either install the SIM in the appropriate slot or change the configuration in order to bring the service up.