Broken system : unable to boot - Question 3

I have a lot of questions about how to repair a broken system. I have already read a lot of things on your forum.
As I did not want to mix different questions with different answers I am going to open a thread for each subject.

Before system got broken :

uname -a
Linux linux-u6go 4.4.104-39-default #1 SMP Thu Jan 4 08:11:03 UTC 2018 (7db1912) x86_64 x86_64 x86_64 GNU/Linux

Hardware info :
— ! —
From that thread :…-boot-scenario

Question 3-a :
After following this thread, and not found any problem in the EFI config, I did a reboot afterb step 19.
This reboot failed.
So I reinstall grub2 as said in step 20, and reboot.
This second reboot failed.

I suppose that the kernel has been removed ( This is the next question in another thread ).
Is it for that reason (no kernel) that the boot jumps to the screen with a grub2 prompt ?


Question 3-b :**
What kind of actions I am supposed to do from the grub2 command line

I must go out.
Question 4 is for tonight.