It seems I have the kernel version 2.6.28. But to say the truth, I flashed the kernel and initfs already (using flasher 3.5). So kernel probably is not the reason of my problems. What about flashing NOLO? Is it safe? My NOLO enables flashing mode and initially starts device (NOKIA logo on the screen), but... who knows what is happening next?

And how to determine rootfs filesystem partition condition using fsck (or other command)?

And, at last, how to find how much free space is left in rootfs partition? I had different values using command df. Maybe lack of space is the reason?