Yoga S1 UltraNav not working under Win10

[kotlety]

Hello everyone,
so I have this strange problem with a Lenovo Yoga S1 (20CD) I recently bought. When I got it, the keyboard was broken (spilled drink, a few buttons were unresponsive) but I managed to install Win10 on it. Everything was working fine (wacom pen, touch screen, touchpad, trackpoint, orientation, light sensor etc). Same thing on Ubuntu (I have dual boot). Problems started when I changed the keyboard. I bought a used one with slightly different buttons (eg big enter instead of a short one) and replaced it. On Ubuntu, everything still works fine, but Win10 started getting BSODs after some software update. I completely reinstalled Win10, using the same iso - touchpad&trackpoint not working, got BSOD after an update again. Reinstalled Win10 once again, now without internet and I still can't get ultranav to work. At the same time, everything works fine when I boot into Ubuntu or boot a live-cd Ubuntu, so it's not a hardware issue for sure.
Does anyone here have any idea what might be wrong? I'm willing to provide more information about the system, just tell me what you need.
Thanks in advance,
K