Hi Ingo,
i have been busy with cows and sowing pasture but now i am back unable to solve the problem. But I am a step further it seems. I am getting into fastboot mode and it doesnt run only loops. Now i tried to follow your advice to reinstall Android10. Now my trouble is that running the command
ricardo@ricardo-MS-7817:~/Downloads/Android10/FP3-REL-Q-3.A.0129-20210805.135600-user-fastbootimage$ sudo ./FP3_flashall
this was the answer: sh: 1: ./linux-x86/fastboot: not found
ricardo@ricardo-MS-7817:~/Downloads/Android10/FP3-REL-Q-3.A.0129-20210805.135600-user-fastbootimage$ sudo chmod +x FP3_flashall_linux
Answer: chmod: cannot access ‘FP3_flashall_linux’: No such file or directory
Looking up the folder of the latest downloaded version the linux x86 folder is empty