Hardware cannot be re-written. It is the physical phone, and there's no way to write something that will make your screen bigger or change the color of your phone. Software can be easily re-written and changed. Those are things like the applications you use on your phone. Some of these apps save changes every time you use them. Firmware is more difficult to change and is changed less frequently. The changes to firmware are also more closely integrated with your phone's hardware than changes to software.
Google periodically pushes out upgrades to the firmware on your Android phone. Usually these are done over the air or OTA. You turn on your phone and it tells you that an update is available. These updates are rolled out, so they don't become available for everyone at once. Sometimes it's hard to be patient, so here's how you can check to see if your update is available now.
How to Check for Updates
- Turn on your phone and hit the MENU button to unlock it.
- Press the home button.
- Press the MENU button.
- Go to Settings by either pressing the screen or using the navigation wheel.
- Scroll down and select the About phone option. This should be the last choice in the list.
Not only will this tell you which firmware version you're running, it will also let you know which build number you're running. In most cases when you read about a build number, they're only talking about the part that starts with RC, ie RC33. There's no point in checking for updates every day if there isn't a new update available.
If you're not running the latest version, press on System updates, and your phone will check to see if there is an update available for you.