efi-boot-stub: enable hook for running (fixup) commands after efibootmgr run

modules/system/boot/loader/efi-boot-stub/efi-boot-stub-builder.sh

@@ -122,3 +122,10 @@ for fn in "@efiSysMountPoint@/efi/nixos/"*; do
         rm -vf -- "$fn"
     fi
 done
+
+# Run any extra commands users may need
+if test -n "@runEfibootmgr@"; then
+  set +e
+  @postEfiBootMgrCommands@
+  set -e
+fi

modules/system/boot/loader/efi-boot-stub/efi-boot-stub.nix

@@ -8,7 +8,7 @@ let
     isExecutable = true;
     inherit (pkgs) bash;
     path = [pkgs.coreutils pkgs.gnused pkgs.gnugrep pkgs.glibc] ++ (pkgs.stdenv.lib.optionals config.boot.loader.efiBootStub.runEfibootmgr [pkgs.efibootmgr pkgs.module_init_tools]);
-    inherit (config.boot.loader.efiBootStub) efiSysMountPoint runEfibootmgr installStartupNsh efiDisk efiPartition;
+    inherit (config.boot.loader.efiBootStub) efiSysMountPoint runEfibootmgr installStartupNsh efiDisk efiPartition postEfiBootMgrCommands;
 
     efiShell = if config.boot.loader.efiBootStub.installShell then
       if pkgs.stdenv.isi686 then
@@ -103,6 +103,17 @@ in
             '';
           };
 
+          postEfiBootMgrCommands = mkOption {
+            default = "";
+            type = types.string;
+            description = ''
+              Shell commands to be executed immediately after efibootmgr has setup the system EFI.
+              Some systems do not follow the EFI specifications properly and insert extra entries.
+              Others will brick (fix by removing battery) on boot when it finds more than X entries.
+              This hook allows for running a few extra efibootmgr commands to combat these issues.
+            '';
+          };
+
         };
       };
     };