Index: lld-10.0.0.src/ELF/Driver.cpp
===================================================================
--- lld-10.0.0.src.orig/ELF/Driver.cpp
+++ lld-10.0.0.src/ELF/Driver.cpp
@@ -693,7 +693,7 @@ getBuildId(opt::InputArgList &args) {
     return {BuildIdKind::None, {}};
 
   if (arg->getOption().getID() == OPT_build_id)
-    return {BuildIdKind::Fast, {}};
+    return {BuildIdKind::Sha1, {}};
 
   StringRef s = arg->getValue();
   if (s == "fast")