Stuck in "Tablet Mode" Detection (Most Common Cause) Even if the screen is fully in laptop position, the hinge sensor (or the Yoga Mode Control service) can get "stuck" and keep the keyboard disabled. Quick fixe to try:

Fully rotate the screen to tablet mode (360° flip), wait 5–10 seconds, then rotate it back to normal laptop mode. Repeat 2–3 times. This often resets the sensor. Close the lid completely (so the laptop sleeps), wait 10–20 seconds, then open it again. Restart the laptop normally (or do a full power cycle: shut down → hold power button 20–30 seconds to discharge → turn back on). If you can use the touchscreen or an external mouse/keyboard: Many users report this instantly revives the keyboard.

If the keyboard works in BIOS but not in Linux, it's almost always this sensor/software issue (not hardware).