During RF initialization, the partial calibration method is used by default for RF calibration. It is done based on the full calibration data which is stored in the NVS. To use this method, please go to ``menuconfig`` and enable :ref:`CONFIG_ESP_PHY_CALIBRATION_AND_DATA_STORAGE`.
Full calibration takes 100 ms longer than the partial calibration method. If boot duration is not of critical importance to the application, the full calibration method is recommended. To switch to the full calibration method, go to ``menuconfig`` and disable :ref:`CONFIG_ESP_PHY_CALIBRATION_AND_DATA_STORAGE`. If you use the default method of RF calibration, there are two ways to add the function of triggering full calibration as a last-resort remedy.
2. Call API :cpp:func:`esp_phy_erase_cal_data_in_nvs` before initializing Wi-Fi and Bluetooth®/Bluetooth Low Energy based on some conditions (e.g., an option provided in some diagnostic mode). In this case, only the PHY namespace of the NVS partition is erased.
One is to use the default initialization data which is located in the header file :idf_file:`components/esp_phy/{IDF_TARGET_PATH_NAME}/include/phy_init_data.h`. It is embedded into the application binary after compiling and then stored into read-only memory (DROM). To use the default initialization data, please go to ``menuconfig`` and disable :ref:`CONFIG_ESP_PHY_INIT_DATA_IN_PARTITION`.
An alternative is to store the initialization data in a PHY data partition. A PHY data partition is included in the default partition table. However, when using a custom partition table, please ensure that a PHY data partition (type: ``data``, subtype: ``phy``) is included in the custom partition table. Whether you are using a custom partition table or the default partition table, if initialization data is stored in a partition, it has to be flashed there, otherwise a runtime error occurs. If you want to use initialization data stored in a partition, go to ``menuconfig`` and enable the option :ref:`CONFIG_ESP_PHY_INIT_DATA_IN_PARTITION`.
