diff --git a/core/grub/build b/core/grub/build
index 25097298..01d9b46c 100755
--- a/core/grub/build
+++ b/core/grub/build
@@ -2,9 +2,10 @@
 
 # Strip '-march' from 'CFLAGS' as per advice from upstream.
 # Fixes build fails on specific hardware.
-CFLAGS=$(printf %s "$CFLAGS" | sed 's/-march=\w* //g')
+CFLAGS=$(printf %s "$CFLAGS" | sed 's/-march=[^ ]* //g')
+export CFLAGS
 
-# Grub is built in a function so the script argument 
+# Grub is built in a function so the script argument
 # needs to be stored.
 pkg_dir=$1