diff --git a/examples/webserver-ipv6-raven/Huginn/makefsdata.h b/examples/webserver-ipv6-raven/Huginn/makefsdata.h
index 654cb1eab..96e60c27b 100644
--- a/examples/webserver-ipv6-raven/Huginn/makefsdata.h
+++ b/examples/webserver-ipv6-raven/Huginn/makefsdata.h
@@ -1,9 +1,9 @@
 #include <avr/eeprom.h>
 
 /* Link layer ipv6 address will become fe80::2 */
-uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02};
-uint8_t default_server_name[16] PROGMEM = "huginn";
-uint8_t default_domain_name[30] PROGMEM = "localhost";
+const uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02};
+const uint8_t default_server_name[16] PROGMEM = "huginn";
+const uint8_t default_domain_name[30] PROGMEM = "localhost";
 uint8_t eemem_mac_address[8]  EEMEM = {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02};
 uint8_t eemem_server_name[16] EEMEM = "huginn";
 uint8_t eemem_domain_name[30] EEMEM = "localhost";
diff --git a/examples/webserver-ipv6-raven/Muninn/makefsdata.h b/examples/webserver-ipv6-raven/Muninn/makefsdata.h
index 51b1a428e..f0da8091a 100644
--- a/examples/webserver-ipv6-raven/Muninn/makefsdata.h
+++ b/examples/webserver-ipv6-raven/Muninn/makefsdata.h
@@ -1,9 +1,9 @@
 #include <avr/eeprom.h>
 
 /* Link layer ipv6 address will become fe80::1 */
-uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
-uint8_t default_server_name[16] PROGMEM = "muninn";
-uint8_t default_domain_name[30] PROGMEM = "localhost";
+const uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
+const uint8_t default_server_name[16] PROGMEM = "muninn";
+const uint8_t default_domain_name[30] PROGMEM = "localhost";
 uint8_t eemem_mac_address[8]  EEMEM = {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
 uint8_t eemem_server_name[16] EEMEM = "muninn";
 uint8_t eemem_domain_name[30] EEMEM = "localhost";
diff --git a/platform/avr-atmega128rfa1/apps/raven-webserver/httpd-fs/makefsdata.h b/platform/avr-atmega128rfa1/apps/raven-webserver/httpd-fs/makefsdata.h
index f532f75e3..512484802 100644
--- a/platform/avr-atmega128rfa1/apps/raven-webserver/httpd-fs/makefsdata.h
+++ b/platform/avr-atmega128rfa1/apps/raven-webserver/httpd-fs/makefsdata.h
@@ -1,9 +1,9 @@
 #include <avr/eeprom.h>
 
 /* Link layer ipv6 address will become fe80::ff:fe:1 */
-uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x00, 0x00, 0xff, 0xfe, 0x00, 0x00, 0x01};
-uint8_t default_server_name[16] PROGMEM = "ATMEGA128rfa1";
-uint8_t default_domain_name[30] PROGMEM = "localhost";
+const uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x00, 0x00, 0xff, 0xfe, 0x00, 0x00, 0x01};
+const uint8_t default_server_name[16] PROGMEM = "ATMEGA128rfa1";
+const uint8_t default_domain_name[30] PROGMEM = "localhost";
 uint8_t eemem_mac_address[8]      EEMEM = {0x02, 0x00, 0x00, 0xff, 0xfe, 0x00, 0x00, 0x01};
 uint8_t eemem_server_name[16]     EEMEM = "ATMEGA128rfa1";
 uint8_t eemem_domain_name[30]     EEMEM = "localhost";
diff --git a/platform/avr-atmega128rfa1/apps/raven-webserver/httpd-fsdata.c b/platform/avr-atmega128rfa1/apps/raven-webserver/httpd-fsdata.c
index 68d44b750..ff217b0f7 100644
--- a/platform/avr-atmega128rfa1/apps/raven-webserver/httpd-fsdata.c
+++ b/platform/avr-atmega128rfa1/apps/raven-webserver/httpd-fsdata.c
@@ -4,9 +4,9 @@
 
 
 /* Link layer ipv6 address will become fe80::ff:fe:1 */
-uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x00, 0x00, 0xff, 0xfe, 0x00, 0x00, 0x01};
-uint8_t default_server_name[16] PROGMEM = "ATMEGA128rfa1";
-uint8_t default_domain_name[30] PROGMEM = "localhost";
+const uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x00, 0x00, 0xff, 0xfe, 0x00, 0x00, 0x01};
+const uint8_t default_server_name[16] PROGMEM = "ATMEGA128rfa1";
+const uint8_t default_domain_name[30] PROGMEM = "localhost";
 uint8_t eemem_mac_address[8]      EEMEM = {0x02, 0x00, 0x00, 0xff, 0xfe, 0x00, 0x00, 0x01};
 uint8_t eemem_server_name[16]     EEMEM = "ATMEGA128rfa1";
 uint8_t eemem_domain_name[30]     EEMEM = "localhost";
diff --git a/platform/avr-raven/apps/raven-webserver/httpd-fs/makefsdata.h b/platform/avr-raven/apps/raven-webserver/httpd-fs/makefsdata.h
index b146f8dc6..d9e704ef2 100644
--- a/platform/avr-raven/apps/raven-webserver/httpd-fs/makefsdata.h
+++ b/platform/avr-raven/apps/raven-webserver/httpd-fs/makefsdata.h
@@ -1,9 +1,9 @@
 #include <avr/eeprom.h>
 
 /* Link layer ipv6 address will become fe80::11:22ff:fe33:4455 */
-uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x11, 0x22, 0xff, 0xfe, 0x33, 0x44, 0x55};
-uint8_t default_server_name[16] PROGMEM = "Contiki-Raven";
-uint8_t default_domain_name[30] PROGMEM = "localhost";
+const uint8_t default_mac_address[8]  PROGMEM = {0x02, 0x11, 0x22, 0xff, 0xfe, 0x33, 0x44, 0x55};
+const uint8_t default_server_name[16] PROGMEM = "Contiki-Raven";
+const uint8_t default_domain_name[30] PROGMEM = "localhost";
 uint8_t eemem_mac_address[8]  EEMEM = {0x02, 0x11, 0x22, 0xff, 0xfe, 0x33, 0x44, 0x55};
 uint8_t eemem_server_name[16] EEMEM = "Contiki-Raven";
 uint8_t eemem_domain_name[30] EEMEM = "localhost";
diff --git a/platform/avr-raven/apps/raven-webserver/httpd.c b/platform/avr-raven/apps/raven-webserver/httpd.c
index 17a1032ff..1327ca6ad 100644
--- a/platform/avr-raven/apps/raven-webserver/httpd.c
+++ b/platform/avr-raven/apps/raven-webserver/httpd.c
@@ -307,8 +307,6 @@ generate_header(void *hstr)
 #endif
 }
 /*---------------------------------------------------------------------------*/
-char http_htm[10]   PROGMEM ="text/html";
-char http_css[ 9]   PROGMEM ="text/css";
 const char httpd_mime_htm[] HTTPD_STRING_ATTR = "text/html";
 const char httpd_mime_css[] HTTPD_STRING_ATTR = "text/css";
 const char httpd_mime_png[] HTTPD_STRING_ATTR = "image/png";