So the menu bars virtual keyboard keys you can see the keys register changing color? And the Caps lock key physically LED is lighting up?
@zhihangong - Lets quickly review how a keyboard works as maybe that will help you see the issue.
In your home you have light switches which turn on and off a given light or sets of lights. A keyboard key switch is not much different within the physical world, just a switch which signals a specialized analog to digital converter (decoder) changing that physical signal used by the keyboard into a digital signal the rest of the system uses.
The test of using the virtual keyboard tells us the physical work is working and working correctly (at least when we tested it) so the keyboard and the wiring (cable) to the logic board is working correctly! As you see the alteration of the screens display of the key when its pressed. So looking for a physical failure won't fix your problem!
This is where the signal from the keyboard decode within the system's OS is getting messed up!
Think of it this way... I have a fancy color changing light build in my hall light the wiring between the switch and socket is standard wiring for a standard lightbulb! So how can I alter the color? Thats don't using a wireless signal to the lightbulb from my phone or tablet application so I can program it as I want it to react.
So now lets jump back to your keyboard issue, so as I started things off we know the simple physical switch to light the light bulb circuit is working! As we can see it within the Virtual keyboard within the OS.
But the way the signal is interpreted is the issue at hand! Just like how the fancy color changing lightbulb needs to be told what to do the OS here has a symbol file (Keyboard Input file) to tell the OS and the Apps how to display this given key (collection of keys) on the screen.
As an example I have a few in my system I select the one I need for the task as I have friends in other countries which prefer non Roman characters (English).
So as an example:
舉個例子，我的系統中有一些字符，我選擇了任務所需的一個，因為我在其他國家的朋友更喜歡非羅馬字符（英語）。
Which is the last paragraph in traditional Chinese Vs Pinyin which is easier to learn and also harder to interpret into English, which I'm sure you know.
At this point I think you need to find someone local to you to help you as the OS and or its files are messed up. I hope your bending of the ribbon cable didn't damage it. I would retest things as I explained above to be sure.
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