diff --git a/vercel-preparation.sh b/vercel-preparation.sh
index cabb5051..77e33112 100755
--- a/vercel-preparation.sh
+++ b/vercel-preparation.sh
@@ -8,10 +8,11 @@ cd "$(dirname "$0")"
 
 mkdir -p apps/backend/.vercel/output/functions/api.func/
 # copying `backend` to `backend/.vercel/...` directly may cause problems
-cp -R apps/backend/. apps/backend-copy/
+cp -RP apps/backend/. apps/backend-copy/
 # `shopt` includes dot-files in the `mv` operation
+du -hc ./apps/backend-copy/ | grep "M"
 (shopt -s dotglob && mv apps/backend-copy/* apps/backend/.vercel/output/functions/api.func/)
-cp -R apps/backend/.vercel/output/functions/api.func/_dot_vercel_copy/output apps/backend/.vercel/
+cp -RP apps/backend/.vercel/output/functions/api.func/_dot_vercel_copy/output apps/backend/.vercel/
 rm -rf apps/backend/node_modules
 du -hc ./apps/backend/ | grep "M"
-cp -R apps/backend apps/frontend/src/backend/
+cp -RP apps/backend apps/frontend/src/backend/