diff --git a/hadrian/src/Base.hs b/hadrian/src/Base.hs
index 9000c114426561da642611ca8ba76d47fea66932..b12b717f66ed984489fd04f62ce95a23290397c2 100644
--- a/hadrian/src/Base.hs
+++ b/hadrian/src/Base.hs
@@ -153,6 +153,8 @@ ghcLibDeps stage iplace = do
         , "settings"
         , "ghc-usage.txt"
         , "ghci-usage.txt"
+        , "post-link.mjs"
+        , "prelude.js"
         ]
     cxxStdLib <- systemCxxStdLibConfPath (PackageDbLoc stage iplace)
     return (cxxStdLib : ps)
diff --git a/hadrian/src/Rules/Generate.hs b/hadrian/src/Rules/Generate.hs
index 9dc13332f3ca8d532a74a34377742d7575da83c9..7bc7b82c54b65efb33d9f11b1467a737cd0bae29 100644
--- a/hadrian/src/Rules/Generate.hs
+++ b/hadrian/src/Rules/Generate.hs
@@ -211,6 +211,9 @@ copyRules = do
         prefix -/- "ghc-interp.js"     <~ return "."
         prefix -/- "template-hsc.h" <~ return (pkgPath hsc2hs -/- "data")
 
+        prefix -/- "post-link.mjs"     <~ pure "utils/jsffi"
+        prefix -/- "prelude.js"        <~ pure "utils/jsffi"
+
         prefix -/- "html/**"           <~ return "utils/haddock/haddock-api/resources"
         prefix -/- "latex/**"          <~ return "utils/haddock/haddock-api/resources"