Thanks for your advices.
I got the system working after finding all commodore pc50 bioses at zimmers.
I tested all of them and the issue persisted, so I started to think that the problem is not in system bios but xt-ide bios.
I had assumed that I could use 386 bios since it's 386 system. After changing to at bios, sytem started to accept no drive option in system bios, and sytem booted normally.