Bricking is when an electronic device becomes unusable, often from a failed software or firmware update. If an update error causes system-level damage, the device may not start up or function at all. In other words, the electronic device becomes a paperweight or a "brick."
The more foundational an update is, the greater its potential to brick a device. For example, a firmware update is more likely to cause bricking than an operating system update. An OS update is higher risk than an application update.
Developers can use preventative measures to prevent bricking. For example, operating system updates typically wait to overwrite old system files until the new files have been fully downloaded and verified. Still, if an update fails at a crucial moment, such as when files are being overwritten, the device may become unusable. If the system cannot boot up and is not updatable, the device is bricked.
Hard vs Soft Bricking
There are two types of bricking — hard and soft. A hard brick is when a device shows little or no signs of life. For example, the power button may light up, but the screen will not turn on. A soft-bricked device functions enough to display an error. For instance, on startup, the screen may display an error message or icon that indicates the operating system is unable to load.
A bricked device may or may not be recoverable. Soft bricks are easier to resolve than hard bricks and can often be fixed by the user. Hard bricks may require special recovery tools only available through the device manufacturer. Therefore, if your device is hard-bricked, you may want to bring it to an authorized repair shop before relegating it to a paperweight.