[Gigachad]

The firmware is what stops you frying components. A good example is that MacOS has software which prevents the speakers from being over driven resulting in physical damage. There are other problematic things like overwriting flash memory which might result in the device not functioning properly.

Most of the time it would be extremely difficult to work out if the user caused the damage or if there was a bug or manufacturing fault. So they just give you a replacement anyway. It would be possible to create extra checks and void flags to try to detect this but that's just extra cost to the product for a feature almost no one cares about.