1 files changed, 18 insertions, 2 deletions
diff --git a/nixpkgs/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py b/nixpkgs/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
index f48a085ce57a..d8baed65c6df 100644
--- a/nixpkgs/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
+++ b/nixpkgs/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
@@ -47,9 +47,9 @@ def write_loader_conf(profile, generation):
         if "@timeout@" != "":
             f.write("timeout @timeout@\n")
         if profile:
-            f.write("default nixos-%s-generation-%d\n" % (profile, generation))
+            f.write("default nixos-%s-generation-%d.conf\n".format(profile, generation))
         else:
-            f.write("default nixos-generation-%d\n" % (generation))
+            f.write("default nixos-generation-%d.conf\n".format(generation))
         if not @editor@:
             f.write("editor 0\n");
         f.write("console-mode @consoleMode@\n");
@@ -197,6 +197,22 @@ def main():
             subprocess.check_call(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "install"])
         else:
             subprocess.check_call(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "--no-variables", "install"])
+    else:
+        # Update bootloader to latest if needed
+        systemd_version = subprocess.check_output(["@systemd@/bin/bootctl", "--version"], universal_newlines=True).split()[1]
+        sdboot_status = subprocess.check_output(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "status"], universal_newlines=True)
+
+        # See status_binaries() in systemd bootctl.c for code which generates this
+        m = re.search("^\W+File:.*/EFI/(BOOT|systemd)/.*\.efi \(systemd-boot (\d+)\)$",
+                      sdboot_status, re.IGNORECASE | re.MULTILINE)
+        if m is None:
+            print("could not find any previously installed systemd-boot")
+        else:
+            sdboot_version = m.group(2)
+            if systemd_version > sdboot_version:
+                print("updating systemd-boot from %s to %s" % (sdboot_version, systemd_version))
+                subprocess.check_call(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "update"])
+
 
     mkdir_p("@efiSysMountPoint@/efi/nixos")
     mkdir_p("@efiSysMountPoint@/loader/entries")