Can't access grub menu

I have successfully installed fedora silverblue in my machine(after many attempts), Now I can boot the system , but can not access grub menu to change images.
I am getting this error at startup
error: …/…/grub-core/fs/fat.c:447: not a FAT filesystem

Here’s how the issue was fixed on Fedora 30. Though, for SilverBlue I would try using rpm-ostree kargs --editor

I tested the installation of Silverblue 31 Beta, then rebase Silverblue 30. This bug was fixed. This comment helped in Silverblue 30: For now you could copy everything that’s in / usr / lib / ostree-boot / efi to / boot / efi in order to have the latest grub2.

Not working.
When I start my laptop grub menu doesn’t appear , but when I reboot my laptop I can see grub menu.

Access Denied ,
How can I copy read only file system?

[aleks@fedy ~]$ su

[root@fedy aleks]# cd /boot/efi
[root@fedy efi]# ls
[root@fedy efi]# cd /usr/lib/ostree-boot/efi
[root@fedy efi]# ls
[root@fedy efi]# cp -r EFI /boot/efi
[root@fedy efi]# cd /boot/efi
[root@fedy efi]# ls
[root@fedy aleks]# exit
[aleks@fedy ~]$ systemctl reboot
To view the grub menu, press ESC at boot time.

Thanks for the explanation.