Your iPhone, iPad, or iPod touch can sometimes get bricked by updating, downgrading or jailbreaking the firmware. If your iPhone is stuck on the Apple logo, or shows the connect to iTunes images when turning it on, your device is not bricked. It can easily be fixed by connecting the device to iTunes and restoring to factory settings and re-installing iOS. To repair the iPhone your first need to put the device on DFU mode by turning off the device first. Then then hold the power and home button for 10 seconds, release the power button and keep holding the home button until the device gets detected in iTunes as Recovery Mode.
Now that the device is in DFU mode, you can restore it through iTunes. On iTunes you can restore the device by clicking the restore button. iTunes will download the firmware and the iDevice will be completely restore to the newest iOS firmware and everything should work fine.
If you’re receiving errors in iTunes while restoring, which happens a lot, check the iTunes iPhone error codes wiki and read the cause of the error. Or try using a different computer.
Is the device does not completely responds to iTunes, then the iPhone may be really bricked. It’s not that easy to brick an iPhone or an iOS device. The device would be bricked only if an internal part is not working. If that’s the case you will need to take the device to Apple for replace or a third-party repair shop.
Image source: geek.com