eSIM (Embedded SIM)

An eSIM is a digital subscriber profile that is downloaded directly into a device's embedded secure chip, replacing the need for a physical plastic SIM card. On dual-SIM smartphones with a physical tray, the network connection for a secondary eSIM profile is typically assigned to the device's secondary identifier, IMEI 2, while devices using eSIM as the primary line can use IMEI 1.

 When activating an eSIM on major cellular networks, users must provide their carrier with both the 32-digit EID number (the secure storage vault) and the IMEI 2 (the digital bridge for the baseband transceiver). Providing the primary IMEI during this digital activation process often causes systemic conflicts, leading to activation failures and delayed network handshakes.