diff --git a/core/grub/build b/core/grub/build
index e2716961..e87b0b3e 100755
--- a/core/grub/build
+++ b/core/grub/build
@@ -8,7 +8,10 @@ export PYTHON=/bin/true
 # the Python tooling. The /bin/true above will create a
 # blank file, this prevents the blank file from overwriting
 # the existing one.
-sed -i 's/mv $@.new $@/:/g' ./*/Makefile.in
+for f in ./*/Makefile.in; do
+    sed 's/mv $@.new $@/:/g' "$f" > _
+    mv -f _ "$f"
+done
 
 # Strip '-march' from 'CFLAGS' as per advice from upstream.
 # Fixes build fails on specific hardware.