Help needed with First installation of EU-ROM

[wer_wien]

Poco X5 pro with latest European (not eu.) ROM. Freshly unlocke.d bootloader. USB debugging on.
Box running Win7. Phone seen by box w BBhen connected for File transfer.
Phone recognised as fastboot device in a Command window.
Unpacked eu.rom file and ran First install.bat. it opens a Command window, but does not get very far.
Would somebody please be kind enough to ln me know what i am doing wrong?

 

[wer_wien]

Well, if nobody is able or willing to help with this problem, possibly there may be help with an alternative way of installing the ROM?
Can i modify the fire myself so it could be installed via TWRP, Mi flash or some other program?
The phone is now rooted and runs the latest stock ROM, but i am not very happy with it and hope for an improvement with the EU.ROM.