diff --git a/project/Core/Src/tftp.c b/project/Core/Src/tftp.c
index d4fa7b3..86d1a37 100644
--- a/project/Core/Src/tftp.c
+++ b/project/Core/Src/tftp.c
@@ -22,7 +22,7 @@ static tftp_custom_file_t virt_file[] = {{.name = "index.txt", .data = NULL, .le
                                          {.name = "virtImage.gif", .data = NULL, .len = 0, .offset = 0},
                                          {.name = "virtText.txt", .data = NULL, .len = 0, .offset = 0}};
 
-int str_cat_str(char* dest, size_t dest_size, const char* src) {
+static int str_cat_str(char* dest, size_t dest_size, const char* src) {
     size_t dest_len = strlen(dest);
     size_t src_len = strlen(src);
     if (dest_len + src_len > dest_size) {
@@ -32,7 +32,7 @@ int str_cat_str(char* dest, size_t dest_size, const char* src) {
     return 0;
 }
 
-int str_cat(char* dest, size_t dest_size, char c) {
+static int str_cat(char* dest, size_t dest_size, char c) {
     size_t dest_len = strlen(dest);
     if (dest_len + 1 > dest_size) {
         return -1;