diff --git a/flashrom.c b/flashrom.c
index ae471da..2837b0d 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -278,7 +278,7 @@
  * needle and remove everything from the first occurrence of needle to the next
  * delimiter from haystack.
  */
-char *extract_param(const char *const *haystack, const char *needle, const char *delim)
+static char *extract_param(const char *const *haystack, const char *needle, const char *delim)
 {
 	char *param_pos, *opt_pos, *rest;
 	char *opt = NULL;