Since this device is nearly 15 years old, standard over-the-air updates won't work. You must use a computer. 1. Requirements

: iTunes will wipe the device and install the firmware. Do not disconnect until you see the "Welcome" screen on the phone. 3. If the Phone is Stuck (DFU Mode)

If your phone is frozen on the Apple logo or won't connect, you must use :

– Often preferred by the community because it is still "signed" by Apple and runs slightly faster on the 3G’s older hardware.

– Recommended for the best performance (speed), though it lacks many features found in iOS 4. 🛠️ How to Install (Flash) the Firmware

is . You can download the IPSW (iPhone Software) files from reputable community databases:

iPhone 3G Glass/Digiter Replacement: Screen Now Black - iFixit