about FOTA

[shayan744]

FOTA = Flash Over The Air. The Sony Ericsson Remote Update Service is a convenient way to easily and remotely update your mobile phone to the latest available software version. This is done over the air; no connection to a PC is needed. The cost for using Sony Ericsson Remote Update Service is your operator's fee for transferring the data to your phone. This varies widely between different operators; if you are uncertain you should contact your operator. User content in the phone, such as images, music, ringtones and videos, is not affected by the update

when we upgrade the firmware fota is automatically updated too.but why we have to write fota sometimes untill phone good works?and when we need write fota?