Christ almighty, I managed to flash it using flashtool after installing the patch x10flasher.jar from here:

http://www.flashtool.net/downloads_linux.php

Unfortunately the result is garbage. The phone first booted and complained that some media service has stopped. And after that it boots into distorted image and reboots all over again.

Flasher showed these warnings:

apps_log is excluded from bundle
diag is excluded from bundle
ssd is excluded from bundle
Qnovo is excluded from bundle
persist is excluded from bundle
userdata is excluded from bundle
Unit 2212 not found in bundle
Unit 2550 not found in bundle
Unit 2553 not found in bundle

I'll try again to flash but this seems painful