@User100 Hey I realize this is old, but if you have not gotten it out of Qaulcomm Crash Dump mode yet the way to do it is getting the MSM tool. You can get the tool with Android 9.0 so that you can boot right into it. Here is the link to the MSM tool. Follow the guide you will find in there it works like a charm. I got the crash dump error twice trying to get it to 9.0.
If your phone is as finicky as mine when you start the process it will give you the sahara error... This is where you have to not listen to the instructions. Keep the phone plugged in and reboot with power + volume up, Then restart the phone with power volume up and you will see that the MSM tool will start the download again once it boots. You can let got of the buttons then and let it do its thing. If you have any questions feel free to reach out and I'll do what I can to help.
Side note.... Rollback option does not work with T-Mobile OnePlus phones.