Ah, thanks for letting us know. I just tried a few reboots with only kp50 and on the 3rd time it got stuck in a loop. So it seems the problem is not with bootmenu, I was just lucky that it booted first time after removing bootmenu. I think I will make a backup and then reflash my N900 to see if I still have any problem, I guess it could be a hardware problem since it seems pretty random - but when the phone is running I have not had any crashes or strange messages in dmesg.