diff --git a/packages/sysutils/busybox-initramfs/build b/packages/sysutils/busybox-initramfs/build
index 1abf53d805..fb04de2490 100755
--- a/packages/sysutils/busybox-initramfs/build
+++ b/packages/sysutils/busybox-initramfs/build
@@ -11,7 +11,7 @@ else
 fi
 
 # optimize for size
-  CFLAGS=`echo $CFLAGS | sed -e "s|-O?|-Os|"`
+  CFLAGS=`echo $CFLAGS | sed -e "s|-O.|-Os|"`
 
 LDFLAGS="$LDFLAGS -fwhole-program"