There are greasy spots under the key caps

If you took out the keys, you could stain them with silicone grease. You can try to clean it off by rubbing the surface with weak alcohol. Be very careful doing this—do not let the alcohol on the inner electronic side of the key. Be fore putting the key in let the liquid dry a few minutes.

There are significant image distortions on the key display

The key or the keyboard may be defective.

Try placing an efficient key instead of that one. If the distortions remain, it is likely that the keyboard is defective.

If the distortions remain when you install that key into other places, it is likely that that key is defective. It needs to be replaced by another one.

I can’t remove the keys

You need to apply some effort to remove the keys using the special tool en closed with the keyboard. Before doing this study the instruction at optimus.artlebedev.com

I have bent a pin contact when installing a key

Before installing keys study the instruction at optimus.artlebedev.com. It also contains recommendations on your problem.

Brightness auto adjustment fails

This mode is program activated. If it is activated but fails, it is likely that there is dust built-up on the light sensor in the right upper corner near the logo. Clean it.

The keyboard doesn’t work after I changed firmware

You can always go back to the first version. Read how to do this at optimus.artlebedev.com.

The keyboard fell and no longer works

The keyboard can withstand light shocks, but the key displays are likely to get damaged if it falls.