Mid-April, maybe earlier, Lenovo provide official 4.3 firmware update, as ROW image, not vibeui, for K900.
It will come as an OTA release, or downloadable install available on Lenovo support site.
Info from Mark Lenovo (forums.lenovo.com).
DAV 701-L have 5.1.1. This OTA update change nothing.
The tutorial is ok, everything is working fine, but i don't now how to enter the google ui style (in developer options switching between Lenovo UI style and Google UI style, is not possible now, as recovery option). After switching, nothing happen...