I have bought sony xperia z4 tablet, and it is unfortunately protected by MXTP. I've tried everything (I think so): using emma, myxperia online, even I sent email to every address that I found on this tablet. Nothing helped and emails was store assistants which tried to unlock it. I've read a lot about it and it is blocked on bootloader level, every time I try connect it to PC there is nothing. Is there any chance to unlock it without superb expensive tech support stuff like sony jig boxes?

pic unrelated