[OnePlus 8 Questions & Answers] Nords99:
Hoping I can find someone who has magic advice to help me get into EDL mode for MSMTool!

Backstory: I was finally getting around to updating my phone (typically rooted and running Evolution X) as it had been almost a year, and the new version of EvoX needed a clean flash. I was able to use MSM Tool just fine to wipe for the clean install (used adb commands to boot into EDL). I OTA updated to A13 and then decided to go forth with flashing the newer ROM. The problem was that I accidentally downloaded the vbmeta.img, recovery.img, and rom.zip for EvoX 9.0 for the Oneplus 8 Pro, not the Oneplus 8. I booted my phone to bootloader, fastboot flashed vbmeta.img and recovery.img, and rebooted to recovery without difficulty. I sideloaded the rom.zip, and only when this was almost done did I notice that it was the .zip (as well as recovery and vbmeta) for the 8 Pro and not the 8. From recovery I enabled ADB again (assuming I could use adb commands to fix from this point) and then selected reboot to bootloader (assuming that from the bootloader I could reflash vbmeta and recovery with the correct versions). At this point, the phone went dark and has been dark since.

So, since selecting 'reboot to bootloader' after flashing the wrong vbmeta and recovery and sideloading the wrong ROM, I have seen no signs of life from the phone. No vibration, nothing on the screen at all. I've tried trying to boot to fastboot by holding volume up + power for various durations, trying to boot to recovery by holding volume down + power for various durations, holding all 3 buttons for various durations - nothing happens, nothing to indicate what mode I might be in, if the phone is on or off, etc.

I've also been trying to use MDMTool again and thus have been attempting to boot into EDL. I wouldn't think I would need to do any updating or changing of my software considering I used it earlier today without difficulty, but other forum threads I've seen have talked a lot about the qualcomm drivers, USB 2.0 vs 3.0, cables, etc. I will note that I'm using a non-original USB-A to USB-C cable and all the ports on my laptop are USB 3.0, not 2.0, but again, I didn't think it would be an issue if it worked fine for me earlier today. Either way, I have been seemingly unable to boot to EDL.

When plugging the phone in, there is no vibration, and nothing appears/refreshes in device manager, same with plugging in holding volume up and volume down. I've tried quite a few times to hold volume up or volume down + power for about 10 seconds, then quick hold volume up and volume down and plug in to try to catch EDL during a restart instead of power being completely off. Again, nothing has showed up in device manager so far, and though I have MSMTool up and ready to start if it detects anything, I've had no such luck. Though, based on some threads trying to similarly boot into EDL mode, it sounds like I might just have to keep trying, as it can be pretty finicky.

I know theoretically it should almost always be possible to use MSMTool, and even in Crashdump mode where nothing works you can bring it back from the brink of hardbrick. Is there still hope for me? Any other advice? Things to try? Just keep on pressing buttons and praying? Any help is appreciated :)

EDIT: Figured out my problem thanks to some help on Discord. My problem is due to the fact that I flashed the wrong xbl (Flashed 8 Pro ROM, which ships the DDR5 xbl, to the 8, which needs the DDR4 xbl), and the only thing that'll get me into back into EDL is with an EDL Deep Flash cable.

If a mod sees this, you can close the thread I guess, I don't really know how to do it on my own. Thanks to anyone who read through this!