The error in your log is:
Installing for x86_64-efi platform. grub-install: error: cannot open `/boot/efi/EFI/ubuntu/shimx64.efi': Read-only file system. Failed: grub-install --target=x86_64-efi
Your ESP must be mounted at /boot/efi and must be mounted read-write in order to upgrade the bootloader.
The error in your log is:
Installing for x86_64-efi platform. efi/EFI/ ubuntu/ shimx64. efi': Read-only file system.
grub-install: error: cannot open `/boot/
Failed: grub-install --target=x86_64-efi
Your ESP must be mounted at /boot/efi and must be mounted read-write in order to upgrade the bootloader.