Once the correct code entered, both SIM slots will be released.
Note I: If your phone is dual-SIM supported, then only order the unlock code for the first SIM slot IMEI. To receive the correct unlock code of a Huawei G6603 phone, we need correct 15-digit IMEI, which can be found on Settings of the phone, or by dialing *#06# as a phone number on the screen. Once the device is unlocked, then it will be network free and can be used with any SIM card. Unlocking of Huawei G6603 is one-time work, means there is no need to input the code again and again.
Once your phone is network-free then you can use it with any supported bands sim-cards. If your phone is locked to a particular network and country, then you can’t use it without unlocking. Means, if your phone is prompting for sim network unlock pin after changing the SIM card then it can be unlocked easily. Sim unlock code of Huawei G6603 is now available.