It is not only not recommended. nrf_nvmc_page_erase() will not work if a SoftDevice is enabled. The NVMC is protected by the SoftDevice so that it can schedule flash operations, so you need to use the SoftDevice API for that. The corresponding SD API is sd_flash_page_erase(). And them you also use sd_flash_write() for writing.
It is not only not recommended. nrf_nvmc_page_erase() will not work if a SoftDevice is enabled. The NVMC is protected by the SoftDevice so that it can schedule flash operations, so you need to use the SoftDevice API for that. The corresponding SD API is sd_flash_page_erase(). And them you also use sd_flash_write() for writing.
