@Moktrull Yeah you need to download the SP Flash Tool and an Android 9 image for your device: https://drive.usercontent.google.com/download?id=18_vFVhQia5Zkedjy9Vz05x_wlNrN-sxe&export=download&authuser=0. This works for me (x606f).
I had some issues using SP Flash Tool on Linux, so I recommend downloading the MTK drivers for Windows and flashing from Windows instead.
Then flash that Android 9 image using SP Flash Tool. Unselect preload inside SP Flash Tool, then flash. After verifying in Settings that it’s Android 9, enter fastboot mode.
Next, download the devel-flashable artifacts from here:
https://gitlab.com/yassinrezai71/lenovo-x606/-/jobs/12500903564/artifacts/download
Unzip it. After unzipping, flash the boot image:
fastboot flash boot out/boot.img
(or wherever the boot.img is located). Then format userdata:
fastboot format:ext4 userdata
After that, flash the Ubuntu image:
fastboot flash system out/ubuntu.img
Finally, reboot:
fastboot reboot
Wait until the device boots into Ubuntu Touch.