building the configuration in /mnt/etc/nixos/configuration.nix...
copying channel...
installing the boot loader...
setting up /etc...
Copied "/nix/store/7m31df5kk2s0s6b4j0whky06g03ayjns-systemd-237/lib/systemd/boot/efi/systemd-bootx64.efi" to "/boot/EFI/systemd/systemd-bootx64.efi".
Copied "/nix/store/7m31df5kk2s0s6b4j0whky06g03ayjns-systemd-237/lib/systemd/boot/efi/systemd-bootx64.efi" to "/boot/EFI/BOOT/BOOTX64.EFI".
Failed to create EFI Boot variable entry: No such file or directory
Traceback (most recent call last):
  File "/nix/store/0xs8qjfv7spb9igclvfz9cfx441w2wb0-systemd-boot-builder.py", line 210, in <module>
    main()
  File "/nix/store/0xs8qjfv7spb9igclvfz9cfx441w2wb0-systemd-boot-builder.py", line 185, in main
    subprocess.check_call(["/nix/store/7m31df5kk2s0s6b4j0whky06g03ayjns-systemd-237/bin/bootctl", "--path=/boot", "install"])
  File "/nix/store/p1bp0kpmxi7nzrla7n7c4waqic0a2myk-python3-3.6.4/lib/python3.6/subprocess.py", line 291, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['/nix/store/7m31df5kk2s0s6b4j0whky06g03ayjns-systemd-237/bin/bootctl', '--path=/boot', 'install']' returned non-zero exit status 1.