diff --git a/.build.sh b/.build.sh
index d16198c..5bdee2e 100644
--- a/.build.sh
+++ b/.build.sh
@@ -20,7 +20,7 @@ clone () {
 # optimizations
 set_cflags () {
   export \
-    CFLAGS="-O3" CPPFLAGS="-O3" LDFLAGS="-Wl,-O3 -Wl,-S" \
+    CFLAGS="-Ofast" CPPFLAGS="-Ofast" LDFLAGS="-Wl,-O3 -Wl,-S" \
     RUSTFLAGS="-C target-cpu=native"
 }
 
diff --git a/build_hr.sh b/build_hr.sh
index d5a5ddc..3566134 100755
--- a/build_hr.sh
+++ b/build_hr.sh
@@ -22,7 +22,8 @@ cargo build \
   --bin resolve \
   --features dnssec-ring \
   --config 'panic="abort"' \
-  --config 'lto="fat"'
+  --config 'lto="fat"' \
+  --config 'codegen-units=1'
 
 echo
 echo '==> Done'