Just found pack of patches for other android phones, which fixes screen mirroring. It's said, that screen mirroring stops working after rooting, and patch disables HDCP completely. There's a patch for Snapdragon 800, which i just applied, and got a confirmation, that it's working, but with opposite effect- screen mirroring service stops with error. So all we need now is to change patch (file /system/vendor/lib/libwfdsm.so) for xperia (and maybe some others) devices. Or it's pretty possible that screen mirroring will work if we just replace current libwfdsm.so with an older version, which surely works. I'm ready to run experiments on my Z1, just need that file from older firmware.