Yesterday I have googled myself tired. So many topics with missing fastboot commands but no real solution.
If it's really needed I might send you a device, I really want to patch in support for certain apps. I might first test the patch on other boox supported device that has root. Going to see who can help me with that. (need to find someone)
I found a nice post too, well worth it:
https://alephsecurity.com/2018/01/22/qualcomm-edl-1/
Tnx for the reply.