Thank you Igor your quick answer!
I apologize for my inattention, I didn't suspect, that "Documentation" button
have another function, than open the drop-down menu. So I changed the display
settings in boot.cmd and banana.bin too and tried some supported resolutions
(720p 60Hz, 720p 50Hz, 480p), but these didn't work for me.
I guess, my monitor hates fruits...
Andrew