diff --git a/contiki/apps/http-strings.c b/contiki/apps/http-strings.c
index 26cbdd5..e2bfd5a 100644
--- a/contiki/apps/http-strings.c
+++ b/contiki/apps/http-strings.c
@@ -1,36 +1,36 @@
-char http_http[8] = 
+const char http_http[8] = 
 /* "http://" */
 {0x68, 0x74, 0x74, 0x70, 0x3a, 0x2f, 0x2f, };
-char http_200[5] = 
+const char http_200[5] = 
 /* "200 " */
 {0x32, 0x30, 0x30, 0x20, };
-char http_301[5] = 
+const char http_301[5] = 
 /* "301 " */
 {0x33, 0x30, 0x31, 0x20, };
-char http_302[5] = 
+const char http_302[5] = 
 /* "302 " */
 {0x33, 0x30, 0x32, 0x20, };
-char http_get[5] = 
+const char http_get[5] = 
 /* "GET " */
 {0x47, 0x45, 0x54, 0x20, };
-char http_10[9] = 
+const char http_10[9] = 
 /* "HTTP/1.0" */
 {0x48, 0x54, 0x54, 0x50, 0x2f, 0x31, 0x2e, 0x30, };
-char http_11[9] = 
+const char http_11[9] = 
 /* "HTTP/1.1" */
 {0x48, 0x54, 0x54, 0x50, 0x2f, 0x31, 0x2e, 0x31, };
-char http_content_type[15] = 
+const char http_content_type[15] = 
 /* "content-type: " */
 {0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e, 0x74, 0x2d, 0x74, 0x79, 0x70, 0x65, 0x3a, 0x20, };
-char http_texthtml[10] = 
+const char http_texthtml[10] = 
 /* "text/html" */
 {0x74, 0x65, 0x78, 0x74, 0x2f, 0x68, 0x74, 0x6d, 0x6c, };
-char http_location[11] = 
+const char http_location[11] = 
 /* "location: " */
 {0x6c, 0x6f, 0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x3a, 0x20, };
-char http_host[7] = 
+const char http_host[7] = 
 /* "host: " */
 {0x68, 0x6f, 0x73, 0x74, 0x3a, 0x20, };
-char http_crnl[3] = 
+const char http_crnl[3] = 
 /* "\r\n" */
 {0xd, 0xa, };