A user equipment (UE) may camp on a network following a SIM bootup. Specifically, the UE may determine that a SIM implementation module of the UE includes a first SIM application (e.g., USIM) associated with a first cellular radio access technology (RAT) (e.g., LTE) and a second SIM application (e.g., CSIM) associated with a second cellular RAT (e.g., CDMA). The UE may then initialize the first SIM application and the second SIM application. The UE may determine whether the network is configured to support both voice and data communications using the first cellular RAT. If so, the UE may initiate camping on the network with the first cellular RAT in response to determining that the first SIM application is ready, but before the second SIM application is ready. If not, the UE may wait until both the first and second SIM applications are ready before initiating camping on the network.