@Dava Sorry to hear that. I just flashed that same rom again and everything works for me. Don't know if this helps you but here are the steps I took:

1. Tablet is not connected to the computer and is turned off
2. Launch mtk_bypass tool and click on "BYPASS". It should say something about waiting on the left.
3. Connect tablet with usb cable and hold Volume up and power button
4. bypass tool should do it's magic and say at the bottom that it was successful
5. Do not disconnect the tablet or turn it off, just close the bypass tool and open spflashtool
6. I selected the Download-Agent "MTK_AllInOne_DA.bin" and the for the scatter file the "*scatter.txt" from the downloaded rom
7. I also checked that everything (including the preloader) is checked
8. I selected the mode "Download only"
9. Click "Download" at the top

After that spflashtool flashed the image and when it was done, it showed me a big green check mark.

Maybe this helps

@Dava I just did this a few days ago, I also had a hard time finding a ROM. I finally got one called "Lenovo_Tab_M10_FHD_Plus_TB-606F_MT6765_HW60_S100055_2001030016_V5.196_BMP_ROW.zip" that worked for me. I had to use spflash tool and cannot remember if I checked or unchecked the preloader, one worked for me while the other did not. I also had to use a tool called "mtk_bypass_rev3" to even be able to flash it with the spflashtool.

I got the ROM from a site called "addrom.com" I cannot say anything about that site or it's safety but it worked for me. If I am allowed to post links here is the download page, just scroll down to find the one I was talking about:
https://addrom.com/stock-rom-firmware-for-lenovo-tab-m10-hd-plus-tb-x606/