ubuntu@ubuntu:~$ sudo parted -l
Model: ATA WDC WDS240G2G0B- (scsi)
Disk /dev/sda: 240GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End    Size    File system  Name                          Flags
 1      1049kB  556MB  555MB   ntfs         Basic data partition          hidden, diag
 2      556MB   660MB  104MB   fat32        EFI system partition          boot, esp         # EFI partition
 3      660MB   676MB  16.8MB               Microsoft reserved partition  msftres
 4      676MB   105GB  104GB   ntfs         Basic data partition          msftdata          # Windows 10
 5      105GB   178GB  73.4GB  ntfs         Basic data partition          msftdata          # Private data
 6      178GB   188GB  9960MB  ntfs         Basic data partition          msftdata          # Private ubuntu data
 7      188GB   240GB  51.8GB  ext4                                                         # Ubuntu 19.10


Model: TOSHIBA USB FLASH DRIVE (scsi)
Disk /dev/sdb: 15.5GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start   End     Size    Type     File system  Flags
 1      1049kB  15.5GB  15.5GB  primary  fat32        boot, lba


ubuntu@ubuntu:~$ sudo mount /dev/sda7 /mnt
ubuntu@ubuntu:~$ sudo mount /dev/sda2 /mnt/boot/efi
ubuntu@ubuntu:~$ sudo mount -o bind /dev /mnt/dev
ubuntu@ubuntu:~$ sudo mount -o bind /sys /mnt/sys
ubuntu@ubuntu:~$ sudo mount -t proc /proc /mnt/proc
ubuntu@ubuntu:~$ sudo cp /proc/mounts /mnt/etc/mtab
cp: '/proc/mounts' and '/mnt/etc/mtab' are the same file
ubuntu@ubuntu:~$ sudo chroot /mnt /bin/bash
root@ubuntu:/# grub-install
Installing for x86_64-efi platform.
grub-install: error: cannot open `/boot/efi/EFI/ubuntu/grubx64.efi': Input/output error.
root@ubuntu:/# grub-install --recheck
Installing for x86_64-efi platform.
grub-install: error: cannot open `/boot/efi/EFI/ubuntu/grubx64.efi': Input/output error.
root@ubuntu:/# cd boot/efi/EFI/
root@ubuntu:/boot/efi/EFI# ls
ls: cannot access 'ubuntu': Input/output error
Boot  HP  Microsoft  ubuntu
root@ubuntu:/boot/efi/EFI#