diff --git a/src/efi.rs b/src/efi.rs
index f600fb45..e0111475 100644
--- a/src/efi.rs
+++ b/src/efi.rs
@@ -481,14 +481,42 @@ impl Component for Efi {
             anyhow::bail!("Failed to find all esp devices");
         };
 
+        // Get old vendor name from installed filetree
+        let old_vendor = {
+            let mut vendor = "";
+            for child in currentf.children.keys() {
+                if child.ends_with(SHIM) {
+                    vendor = child.strip_suffix(&format!("/{SHIM}")).unwrap_or("");
+                    break;
+                }
+            }
+            vendor.to_owned()
+        };
+
         for esp in esp_devices {
             let destpath = &self.ensure_mounted_esp(rootcxt.path.as_ref(), Path::new(&esp))?;
-            let destdir = openat::Dir::open(&destpath.join("EFI")).context("opening EFI dir")?;
+            let dest_efi = destpath.join("EFI");
+            let destdir = openat::Dir::open(&dest_efi).context("opening EFI dir")?;
             validate_esp_fstype(&destdir)?;
+
             log::trace!("applying diff: {}", &diff);
             filetree::apply_diff(&updated, &destdir, &diff, None)
                 .context("applying filesystem changes")?;
 
+            // Install grub.cfg under new vendor
+            {
+                // Get new vendor name
+                let sysroot = rootcxt.path.as_std_path();
+                let Some(new_vendor) = self.get_efi_vendor(&sysroot.join(&updated_path))? else {
+                    anyhow::bail!("Failed to find efi vendor in new update");
+                };
+                if new_vendor != old_vendor && destdir.exists(&old_vendor)? {
+                    grubconfigs::install(sysroot_dir, None, Some(&new_vendor), true)?;
+                    destdir.remove_all(&old_vendor)?;
+                    assert!(destdir.exists(format!("{new_vendor}/{}", grubconfigs::GRUBCONFIG))?);
+                }
+            }
+
             // Do the sync before unmount
             fsfreeze_thaw_cycle(destdir.open_file(".")?)?;
             drop(destdir);
@@ -609,7 +637,7 @@ impl Component for Efi {
 
         // Does not support multiple shim for efi
         if shim_files.len() > 1 {
-            anyhow::bail!("Found multiple {SHIM} in the image");
+            anyhow::bail!("Found multiple {SHIM} in the image: {:?}", shim_files);
         }
         if let Some(p) = shim_files.first() {
             let p = p
diff --git a/src/grubconfigs.rs b/src/grubconfigs.rs
index 17be02a4..e80d7a3a 100644
--- a/src/grubconfigs.rs
+++ b/src/grubconfigs.rs
@@ -12,7 +12,7 @@ use crate::freezethaw::fsfreeze_thaw_cycle;
 
 /// The subdirectory of /boot we use
 const GRUB2DIR: &str = "grub2";
-const CONFIGDIR: &str = "/usr/lib/bootupd/grub2-static";
+const CONFIGDIR: &str = "usr/lib/bootupd/grub2-static";
 const DROPINDIR: &str = "configs.d";
 // The related grub files
 const GRUBENV: &str = "grubenv";
@@ -43,11 +43,10 @@ pub(crate) fn install(
     }
 
     let configdir = if let Some(src_root) = src_root {
-        // strip the leading `/` to make the path relative to the given
-        // source root
-        src_root.sub_dir(Path::new(CONFIGDIR).strip_prefix("/")?)?
+        src_root.sub_dir(CONFIGDIR)?
     } else {
-        openat::Dir::open(Path::new(CONFIGDIR))?
+        // Open / if there is no source root
+        openat::Dir::open("/")?.sub_dir(CONFIGDIR)?
     };
 
     let mut config = String::from("# Generated by bootupd / do not edit\n\n");
@@ -58,7 +57,7 @@ pub(crate) fn install(
         .read_to_string(&mut pre)?;
     config.push_str(pre.as_str());
 
-    let dropindir = configdir.sub_dir(Path::new(DROPINDIR))?;
+    let dropindir = configdir.sub_dir(DROPINDIR)?;
     // Sort the files for reproducibility
     let mut entries = dropindir
         .list_dir(".")?
@@ -85,7 +84,7 @@ pub(crate) fn install(
 
     let grub2dir = bootdir.sub_dir(GRUB2DIR)?;
     grub2dir
-        .write_file_contents("grub.cfg", GRUBCONFIG_FILE_MODE, config.as_bytes())
+        .write_file_contents(GRUBCONFIG, GRUBCONFIG_FILE_MODE, config.as_bytes())
         .context("Copying grub-static.cfg")?;
     println!("Installed: grub.cfg");
 
@@ -113,7 +112,7 @@ pub(crate) fn install(
     if let Some(vendordir) = installed_efi_vendor {
         log::debug!("vendordir={:?}", &vendordir);
         let vendor = PathBuf::from(vendordir);
-        let target = &vendor.join("grub.cfg");
+        let target = &vendor.join(GRUBCONFIG);
         let dest_efidir = target_root
             .sub_dir_optional("boot/efi/EFI")
             .context("Opening /boot/efi/EFI")?;