Thanks to the great job the guys at xda-development, the latest build (last time it was September 19) works stable.
The change I made in rootfs.img is not necessary anymore - swap file is created in ramzsswap.
Two serious problems still exist:
1. An attempt to turn off the WiFi after it actively used (and probably when the swap file is in use) leads to total system hang.
2. Sometimes, there is no audio in phone calls.
Did not mention, the camera and bluetooth do not work at all. Hopefully they will fix that as well.