diff --git a/.github/workflows/mononoke_linux.yml b/.github/workflows/mononoke_linux.yml
index 67daf17ba3e23..760ec25450e2d 100644
--- a/.github/workflows/mononoke_linux.yml
+++ b/.github/workflows/mononoke_linux.yml
@@ -177,14 +177,14 @@ jobs:
     - name: Build rust-shed
       run: python3 build/fbcode_builder/getdeps.py --allow-system-packages build --free-up-disk --no-tests rust-shed
     - name: Build mononoke
-      run: python3 build/fbcode_builder/getdeps.py --allow-system-packages build --src-dir=. mononoke  --project-install-prefix mononoke:/usr/local
+      run: python3 build/fbcode_builder/getdeps.py --allow-system-packages build --src-dir=. mononoke  --project-install-prefix mononoke:/
     - name: Copy artifacts
-      run: python3 build/fbcode_builder/getdeps.py --allow-system-packages fixup-dyn-deps --strip --src-dir=. mononoke _artifacts/linux  --project-install-prefix mononoke:/usr/local --final-install-prefix /usr/local
+      run: python3 build/fbcode_builder/getdeps.py --allow-system-packages fixup-dyn-deps --strip --src-dir=. mononoke _artifacts/linux  --project-install-prefix mononoke:/ --final-install-prefix /usr/local
     - uses: actions/upload-artifact@v4
       with:
         name: mononoke
         path: _artifacts
     - name: Test mononoke
-      run: python3 build/fbcode_builder/getdeps.py --allow-system-packages test --src-dir=. mononoke  --project-install-prefix mononoke:/usr/local
+      run: python3 build/fbcode_builder/getdeps.py --allow-system-packages test --src-dir=. mononoke  --project-install-prefix mononoke:/
     - name: Show disk space at end
       run: df -h
diff --git a/build/fbcode_builder/getdeps.py b/build/fbcode_builder/getdeps.py
index ae12922f0ce31..c8b03802495be 100755
--- a/build/fbcode_builder/getdeps.py
+++ b/build/fbcode_builder/getdeps.py
@@ -960,6 +960,7 @@ def write_job_for_platform(self, platform, args):  # noqa: C901
         build_opts = setup_build_options(args, platform)
         ctx_gen = build_opts.get_context_generator()
         loader = ManifestLoader(build_opts, ctx_gen)
+        self.process_project_dir_arguments(args, loader)
         manifest = loader.load_manifest(args.project)
         manifest_ctx = loader.ctx_gen.get_context(manifest.name)
         run_on = self.get_run_on(args)
@@ -1147,8 +1148,10 @@ def write_job_for_platform(self, platform, args):  # noqa: C901
 
             project_prefix = ""
             if not build_opts.is_windows():
-                project_prefix = (
-                    " --project-install-prefix %s:/usr/local" % manifest.name
+                prefix = loader.get_project_install_prefix(manifest) or "/usr/local"
+                project_prefix = " --project-install-prefix %s:%s" % (
+                    manifest.name,
+                    prefix,
                 )
 
             # If we have dep from same repo, we already built it and don't want to rebuild it again