Hey @martoni !
Actually, your thread was my main source of information when I tried to install /e/ OS on my OnePlus 6T, so thanks a lot!
But sadly, it seems it wasn’t enough… I did succeed to install TWRP with your information, but then, when I installed /e/ OS, I got the infamous fastboot boot-loop…
I think a better understanding of A/B partition may be the key to successfully install this OS in one shot.
I would be glad if you could write the full installation process, for I could check if I didn’t miss anything.
In the meantime, I’m gonna read stuff about A/B partioning, and maybe try those two threads:
This last thread is about a OnePlus 6, but has a well detailed installation process for A/B partitioned device.