I finally tried to update /e/OS on my OnePlus 8T Kebab this morning after a couple years, following the instructions for flashing the provided dtbo.img and vbmeta.img before flashing the /e/os recovery in fastboot.
The commands seem to execute in my terminal without issue, however when rebooting the device either physically or through Fastboot, the phone is unable to load recovery and bootloops into Fastboot. I don’t even see the recovery display.
I tried flashing the last version of TWRP for this device from 2022, and it gets as far as showing me the TWRP 3.7 boot screen before locking up and needing a restart.
Any ideas what I can do to fix this? Thankfully fastboot still works, so hopefully I can do something to repair the recovery.
Edit: I am now trying to use the MSM Download Tool from OnePlus to recover the device, but I am unable to get the phone into EDL mode, it is now persistently bootlooping to CrashDump mode after I first tried flashing payload.bin from “Fastboot Enhanced”.
I am unable to get the phone into EDL mode for the MSM tool to repair. I am now stuck in the well known hell of having several XDA forum tabs open along with a folder of random poorly named .zip files of drivers and obscure tools dating back several years trying to get any response form the phone.
Nothing I do seems to get the phone out of CrashDump mode now, MSM is able to detect the device and the Qualcom drivers seem to be working but it never starts flashing.
Edit: I was finally able to get the MSM tool to start communicating with the device. I don’t know if it matters, but I stopped trying to use my desktop and instead am using an old HP laptop now.
I think timing is extremely unforgiving when it comes to getting MSM to recognize the phone for EDL mode before defaulting to Crashdump.
I just kept turning the phone completely off (USB unplugged), holding down Vol Down + Vol Up, and connecting the USB cable with the MSM tool already open, and as soon as the computer would make a sound indicating it picked up the device I hit “start” in MSM before anything actually displayed on the phone itself and it finally picked it up.
I’m back to stock now, and will start from scratch with getting the latest /e/ onto the phone. I’ll mark this as solved.