Hello everybody.
The only thing the easy installer did for me was unlocking the bootloader and very easily bricked my Oneplus 8 pro to the state that only the bootloader was working.
Installing recovery and via fastboot did not work.
I had to boot Windows 10 and followed the best and most straightforward method I found on the oneplus community site:
https://community.oneplus.com/thread/1541327
There is a link to the “unbrick tool” for different devices which includes the ROM file and the MSM download tool for EU, Global and Indian versions, along with the link to the Qualcomm Drivers.
Also helpful is the following video and the description on XDA developers. However, I did not use the files from the XDA forum post, but from Oneplus community, which indeed worked flawlessly.
https://www.youtube.com/watch?v=zYn1vD8V9rc&ab_channel=ShahinurIslam
I first downloaded the tool for EU region, and MSM tool stopped with an error message “unsupported target”. Apparently I had bought a Global version without knowing, and successfully repeated the procedure with the Global MSM download tool.