I got the T (dev) build to work on the guacamole (7 Pro) tonight after a lot of backtracking and spending a whole day staring at a non-working touchscreen after a fresh install of S (dev).
I believe the key is properly extracting & flashing the 2 image files (dtbo.img, vbmeta.img) referred to in this section of the manual install (e.g. on guacamole): https://doc.e.foundation/devices/guacamole/install#flashing-additional-partitions
… according to this extraction method, and ensuring that the versions of these 2 additional partitions flashed are the same as the ones in the ZIP being installed: https://community.e.foundation/t/oneplus-platform-how-to-get-dtbo-img-vbmeta-img/52571/4
All in all I went from a 7 Pro on stock OxygenOS 12 to /e/OS T (dev) by the following route:
- revert OOS 12 to a stock OOS 11 using MSMDowloadTool
- unlock the bootloader according to usual /e/OS instructions
- install OxygenUpdater app to update firmware to OOS 12
- extract & flash the 2 “additional” partitions from the T (dev) ZIP file payload as described above
- download & flash the latest /e/OS recovery available for my device
- sideload T (dev), reboot, and it’s done (working touchscreen + /e/OS Android 13).
