You have not said what type of mobile phone you have ??....
Updating the software or firmware on your mobile phone can fix some unstable problems with cell phones.
Cell Phone Firmware Flashing
Cell phone firmware flashing is the process by which a user
upgrades a phone's mobile operating system or internal memory applications.
Flashing can provide a brand-new version of a mobile OS or
simply provide bug fixes when phones are having specific issues.
Types of Upgrades
Upgrading an operating system, such as moving from Google
Android 2.0 to Google Android 2.1, is the first function of firmware updates.
Installing better-performing software is the second type of upgrade.
New mobile operating systems typically offer advanced
features and better-performing systems (faster, more streamlined functions).
Software updates often fix hardware and software issues,
such as increasing the strength of a phone's GPS or increasing cell phone
reception and email capabilities, among other new features
Flashing a phone will not "unlock" your phone.
It will also not remove carrier restrictions placed on the
Flashing a phone will also not turn your phone from CDMA to
GSM or vice versa, since this requires hardware modifications.
Be sure to flash your phone on a full battery.
A partial flash when a phone turns off can lead to phone
"bricking," in which the phone will stop operating completely.
In most cases you can simply reflash the device; in others,
you will have to send the phone in for repair.
In order to perform a cell phone unlock on some carrier-specific
devices, you will be required to perform a firmware flash.
This "flashing procedure" is most often seen with
various iPhone "jailbreaking" methods.
Typically, this type of flashing is not allowed by the
manufacturer and is considered a "hack."
By replacing the manufacturer's OS with a hacked OS, it
becomes possible to unlock the phone.