Problem was with strange keyboard map - pressing Enter on external keyboard did nothing in most of cases. After some digging and comparing I found that it emmits DPAD_Center instead of Enter.
It can be fixed by editing /system/usr/keylayouts/Generic.kl and replacing
key 28 DPAD_CENTERto
key 28 ENTERIn a script (run as root):
mount -o remount,rw /system && \ busybox sed -i 's@key 28[[:blank:]].*@key 28 ENTER@' /system/usr/keylayouts/Generic.kl && \ mount -o remount,ro /system