diff --git a/distros/distro-overlay.nix b/distros/distro-overlay.nix
index b3a779a34e..d323d47de3 100644
--- a/distros/distro-overlay.nix
+++ b/distros/distro-overlay.nix
@@ -315,15 +315,6 @@ let
       nativeBuildInputs = nativeBuildInputs ++ [ self.qt5.wrapQtAppsHook ];
     });
 
-    rviz-ogre-vendor = rosSuper.rviz-ogre-vendor.overrideAttrs ({
-      preFixup ? "", ...
-    }: {
-      preFixup = ''
-        # Prevent /build RPATH references
-        rm -r ogre_install
-      '' + preFixup;
-    });
-
     rxcpp-vendor = patchVendorUrl rosSuper.rxcpp-vendor {
       url = "https://github.com/ReactiveX/RxCpp/archive/v4.1.0.tar.gz";
       sha256 = "1smxrcm0s6bz05185dx1i2xjgn47rq7m247pblil6p3bmk3lkfyk";
diff --git a/distros/rolling/overrides.nix b/distros/rolling/overrides.nix
index b6cc294b08..fa9a585184 100644
--- a/distros/rolling/overrides.nix
+++ b/distros/rolling/overrides.nix
@@ -73,9 +73,24 @@ rosSelf: rosSuper: with rosSelf.lib; {
     };
   };
 
-  rviz-ogre-vendor = patchVendorUrl rosSuper.rviz-ogre-vendor {
-    url = "https://github.com/OGRECave/ogre/archive/v1.12.10.zip";
-    sha256 = "sha256-lZDLywgShlWeWah7oTnyKBTqzN505LJKbQbgXRfJXlk=";
+  rviz-ogre-vendor = patchAmentVendorGit rosSuper.rviz-ogre-vendor {
+    url = "https://github.com/OGRECave/ogre.git";
+    rev = "v1.12.10";
+    fetchgitArgs.hash = "sha256-Z0ixdSmkV93coBBVZ5R3lPLfVMXRfWsFz/RsSyqPWFY=";
+    tarSourceArgs.hook = let
+      version = "1.79";
+      imgui = (self.fetchFromGitHub rec {
+        name = "${repo}-${version}";
+        owner = "ocornut";
+        repo = "imgui";
+        rev = "v${version}";
+        hash = "sha256-GIVhZ8Q7WebfHeKeJdVABXrTT26FOS7updncbv2LRnQ=";
+      });
+      imguiTar = tarSource { } imgui;
+    in ''
+      substituteInPlace Components/Overlay/CMakeLists.txt \
+        --replace ${escapeShellArg imgui.url} file://${escapeShellArg imguiTar}
+    '';
   };
 
   urdfdom = rosSuper.urdfdom.overrideAttrs ({
diff --git a/lib/default.nix b/lib/default.nix
index 059bda2b15..79f0c53f07 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -7,30 +7,79 @@ with lib;
     s = composeManyExtensions overlays s {};
   in s;
 
+  # Create a tarball of a package source. If the source is already an archive,
+  # it will be unpacked and repacked as a tarball.
+  tarSource = {
+    compress ? false,
+    hook ? ""
+  }: src: self.runCommand ("${src.name}.tar" + lib.optionalString compress ".gz") { inherit src; } ''
+    unpackPhase
+    pushd "$sourceRoot"
+    ${hook}
+    popd
+    tar --sort=name \
+      --format=gnu \
+      --owner=0 --group=0 --numeric-owner \
+      ${lib.optionalString compress "-z"} \
+      -cf "$out" "$sourceRoot"
+  '';
+
   patchVendorUrl = pkg: {
-    url, sha256,
+    url, hash ? "", sha256 ? "",
     originalUrl ? url,
     file ? "CMakeLists.txt"
   }: pkg.overrideAttrs ({
     postPatch ? "", ...
   }: {
     postPatch = ''
-      substituteInPlace '${file}' \
-        --replace '${originalUrl}' '${self.fetchurl { inherit url sha256; }}'
+      substituteInPlace ${escapeShellArg file} \
+        --replace ${escapeShellArg originalUrl} ${escapeShellArg (self.fetchurl { inherit url hash sha256; })}
     '' + postPatch;
   });
 
   patchVendorGit = pkg: {
     url,
+    originalUrl ? url,
     file ? "CMakeLists.txt",
     fetchgitArgs ? {}
   }: pkg.overrideAttrs ({
     postPatch ? "", ...
   }: {
     postPatch = ''
-      sed -i '\|GIT_REPOSITORY\s.*${escapeShellArg url}|c\
+      sed -i '\|GIT_REPOSITORY\s.*${originalUrl}|c\
         URL "${self.fetchgit ({ inherit url; } // fetchgitArgs)}"' \
-        '${file}'
+        ${escapeShellArg file}
+    '' + postPatch;
+  });
+
+  # Patch a vendored download that uses ament_vendor() with a Git repo as the
+  # source.
+  patchAmentVendorGit = pkg: {
+    url,
+    originalUrl ? url,
+    rev, # Must correspond to the VCS_VERSION argument
+    file ? "CMakeLists.txt",
+    fetchgitArgs ? {},
+    tarSourceArgs ? {}
+  }: pkg.overrideAttrs ({
+    nativeBuildInputs ? [],
+    postPatch ? "", ...
+  }: let
+    # ament_vendor doesn't allow patches for path inputs, so we have to pack it
+    # into a tar first. Additionally, vcstool only accepts tarballs with the
+    # version number as the root directory name.
+    vendor = lib.tarSource tarSourceArgs (self.fetchgit (fetchgitArgs // {
+      name = rev;
+      inherit url rev;
+    }));
+  in {
+    # CMake ExternalProject patches are applied with git apply
+    nativeBuildInputs = nativeBuildInputs ++ [ self.git ];
+    postPatch = ''
+      sed -i '\|VCS_URL\s*${originalUrl}|c\
+        VCS_URL "file://${vendor}"\
+        VCS_TYPE tar' \
+        ${lib.escapeShellArg file}
     '' + postPatch;
   });