Allegedly, there are two versions 301 and 301 plus, and 301 should have the same hardware as cybook. There are also two versions of FW, one for 301 and one for 301 plus. So if anyone wants to try it, the 301 FW should be the right one. Though I can't warrant that, if you reflash your cybook, you're doing so at your own risk.
I would go for it myself but I don't know how to get the original bookeen FW back on the device if I'm not satisfied with the pocketbook's FW.
As for the instructions, they can be found in the archive along with the image file and easily translated by google translate (ukrainian -> english).
I've heard that the cybook's updates are not complete firmware, so I can't reflash the device back with them if anything goes wrong, is that correct?
The FW can also be found on the-ebook.org forums.