add efi var install option

disko-install

@@ -10,6 +10,9 @@ Usage: $0 [OPTIONS]
   --show-trace                Show the stack trace on error.
   -h, --help                  Show this help message.
   --reference-lock-file FILE  Use the specified lock file as a reference for the Nix store.
+  --write-efi-boot-entries    Write EFI boot entries to the NVRAM of the system for the installed system.
+                              Specify this option if you plan to boot from this disk on the current machine,
+                              but not if you plan to move the disk to another machine.
 EOF
 }
 
@@ -34,6 +37,7 @@ nix_args=(
 )
 dry_run=
 diskoAttr=diskoScript
+writeEfiBootEntries=false
 declare -A diskMappings
 
 parseArgs() {
@@ -61,6 +65,9 @@ parseArgs() {
     --show-trace)
       nix_args+=("$1")
       ;;
+    --write-efi-boot-entries)
+      writeEfiBootEntries=true
+      ;;
     --mode)
       if [[ $# -lt 2 ]]; then
         echo "Option $1 requires an argument" >&2
@@ -150,6 +157,7 @@ main() {
     --argstr flake "$flake" \
     --argstr flakeAttr "$flakeAttr" \
     --argstr rootMountPoint "$mountPoint" \
+    --arg writeEfiBootEntries "$writeEfiBootEntries" \
     --arg diskMappings "$(serialiaseArrayToNix diskMappings)" \
     -A installToplevel \
     -A "$diskoAttr")

docs/disko-install.md

@@ -111,3 +111,17 @@ or attaching it to a qemu-vm:
 ```
 $ sudo qemu-kvm -enable-kvm -hda /dev/sda
 ```
+
+### Persisting boot entries to EFI vars flash
+
+Disko-install is designed for NixOS installations on portable storage or disks that may be transferred between computers.
+As such, it does not modify the host's NVRAM by default.
+To ensure your NixOS installation boots seamlessly on new hardware or to prioritize it in your current machine's boot order,
+use the --write-efi-boot-entries option:
+
+```console
+$ sudo nix run 'github:nix-community/disko#disko-install' -- --write-efi-boot-entries --flake '/tmp/config/etc/nixos#mymachine' --disk main /dev/sda
+```
+
+This command installs NixOS with Disko-install and sets the newly installed system as the default boot option,
+without affecting the flexibility to boot from other devices if needed.

install-cli.nix

@@ -1,7 +1,7 @@
 { flake
 , flakeAttr
 , diskMappings
-, canTouchEfiVariables ? false
+, writeEfiBootEntries ? false
 , rootMountPoint ? "/mnt"
 }:
 let
@@ -32,7 +32,7 @@ let
     };
    installSystem = originalSystem.extendModules {
      modules = [({ lib, ... }: {
-       boot.loader.efi.canTouchEfiVariables = lib.mkVMOverride canTouchEfiVariables;
+       boot.loader.efi.canTouchEfiVariables = lib.mkVMOverride writeEfiBootEntries;
        boot.loader.grub.devices = lib.mkVMOverride diskoSystem.config.boot.loader.grub.devices;
      })];
    };