Nixos-rebuild switch activates but no change after reboot

When i use sudo nixos-rebuild switch it completes without error and activates all services and programs, but after reboot everything is gone. Here is my boot config from configuration.nix, I have used grub to enable osprober for multibooting capabilities instead of systemd-boot.

my boot config in configuration.nix


# # Bootloader settings
  boot.loader = {
#     systemd-boot.enable = true;
    grub = {
      enable = true;
      zfsSupport = true;
      devices = ["nodev"];
      efiSupport = true;
      useOSProber = true;

  # Filesystem support
  boot.supportedFilesystems = [ "ntfs" ];

  # ZFS settings
  boot.kernelPackages = config.boot.zfs.package.latestCompatibleLinuxPackages;
  boot.zfs.extraPools = [ "zpool_name" ];
  services.zfs.autoScrub.enable = true;


I have also create more detailed log of system config and changes in variables at Sudo nixos-rebuild switch do not update boot entry and previous configuratin is booted

The cause for this is typically that the boot partition isn’t mounted properly and the generation it attempts to boot is therefore never actually changed. Verify that this is the case.

Note that systemd-boot is able to discover Windows installations at runtime by default.