Am 02.10.20 um 11:12 schrieb Petr Pisar:
On Thu, Oct 01, 2020 at 11:07:28AM -0700, Samuel Sieb wrote:

On 10/1/20 5:52 AM, Marius Schwarz wrote:


          

            
Is it possible to boot from the stick and then perform a grub-install
with an old grub?



          

          
This attempt failed too:

#  grub2-install /dev/sda
grub2-install: Fehler: /usr/lib/grub/x86_64-efi/modinfo.sh existiert
nicht. Bitte geben Sie --target oder --directory an.

and that file seems not to be part of any package. There is only one for
"i386-pc".


        

        
You can't (and must not!) use grub2-install on an EFI system.


      

      
Of course you have. How else would you get GRUB EFI executable onto the boot
partition and register it into boot environments?

But the correct invocation for EFI systems is different. You just use
"grub2-install" without the disk device name.

    

    If you do not state the devicename, how does grub choose the correct
    drive? I don't want to overwrite the bootloader on the ssd. 

    

    by entering "grub2-install /dev/sdb" where sdb was the usb drive,
    grub2 removed the working boot config from .. you guessed it by
    now.. the ssd :(

    

    The repair try, done by the docs.fp.org....bootloading-with-grub2
    guide, honestly said, it wants to install i386 on a clearly x64 
    system. 

    

    

    FYI: Not working without manual corrections

    

    insmod lvm

    insmod xfs

    set root=(hd0,gpt3)

    configfile /grub2/grub.cfg

    linux /vmlinuz-5.8.10....

    initrd /initramfs-5.8.10....

    boot

    

    Q: Why is configfile read, but not used if anything important is in
    it i.e. the sysroot options passed to "linux" to find the decrypted
    luks partition?

    

    AFTER this: i managed to boot the system, by manually mounting the
    dm-0 device to /sysroot

    

    BUT:

    
grub2-mkconfig -o /boot/grub2/grub.cfg


    
grub2-install --boot-directory=/boot /dev/nvm0n1

did not succeed in recreating a working boot environment, in fact, nothing changed. Still not presenting a grub menu, where grub2-mkconfig said, it created the menu. 
(i hate lying tools)


    Q: What did anaconda different on the first installation of Fedora,
    to make it work?

    

    --> HELP needed <-- 

    

    

    Lesson learned: once it's on a system, don't play with
    grub2-install. 

    

    Marius