diff --git a/dist/tools/doccheck/exclude_patterns b/dist/tools/doccheck/exclude_patterns
index 4d7937cd3f..b77b225723 100644
--- a/dist/tools/doccheck/exclude_patterns
+++ b/dist/tools/doccheck/exclude_patterns
@@ -12275,6 +12275,7 @@ sys/include/net/coap\.h:[0-9]+: warning: Member COAP_CODE_REQUEST_ENTITY_TOO_LAR
 sys/include/net/coap\.h:[0-9]+: warning: Member COAP_CODE_SERVICE_UNAVAILABLE \(macro definition\) of group net_coap is not documented\.
 sys/include/net/coap\.h:[0-9]+: warning: Member COAP_CODE_UNAUTHORIZED \(macro definition\) of group net_coap is not documented\.
 sys/include/net/coap\.h:[0-9]+: warning: Member COAP_CODE_UNPROCESSABLE_ENTITY \(macro definition\) of group net_coap is not documented\.
+sys/include/net/coap\.h:[0-9]+: warning: Member COAP_CODE_TOO_MANY_REQUESTS \(macro definition\) of group net_coap is not documented\.
 sys/include/net/coap\.h:[0-9]+: warning: Member COAP_CODE_UNSUPPORTED_CONTENT_FORMAT \(macro definition\) of group net_coap is not documented\.
 sys/include/net/coap\.h:[0-9]+: warning: Member COAP_CODE_VALID \(macro definition\) of group net_coap is not documented\.
 sys/include/net/coap\.h:[0-9]+: warning: Member COAP_DEFAULT_LEISURE \(macro definition\) of group net_coap is not documented\.
diff --git a/sys/include/net/coap.h b/sys/include/net/coap.h
index 1d31ccd7e9..f4adf74ee1 100644
--- a/sys/include/net/coap.h
+++ b/sys/include/net/coap.h
@@ -150,6 +150,7 @@ extern "C" {
 #define COAP_CODE_REQUEST_ENTITY_TOO_LARGE   ((4 << 5) | 13)
 #define COAP_CODE_UNSUPPORTED_CONTENT_FORMAT ((4 << 5) | 15)
 #define COAP_CODE_UNPROCESSABLE_ENTITY       ((4 << 5) | 22)
+#define COAP_CODE_TOO_MANY_REQUESTS          ((4 << 5) | 29)
 /** @} */
 
 /**
diff --git a/sys/include/net/gnrc/netif.h b/sys/include/net/gnrc/netif.h
index 9324a56a85..b9b4718525 100644
--- a/sys/include/net/gnrc/netif.h
+++ b/sys/include/net/gnrc/netif.h
@@ -593,7 +593,7 @@ static inline int gnrc_netif_ipv6_groups_get(const gnrc_netif_t *netif,
  * @return  -ENOTSUP, if @p netif doesn't support IPv6.
  */
 static inline int gnrc_netif_ipv6_group_join(const gnrc_netif_t *netif,
-                                             ipv6_addr_t *group)
+                                             const ipv6_addr_t *group)
 {
     assert(netif != NULL);
     assert(group != NULL);
@@ -615,7 +615,7 @@ static inline int gnrc_netif_ipv6_group_join(const gnrc_netif_t *netif,
  * @return  -ENOTSUP, if @p netif doesn't support IPv6.
  */
 static inline int gnrc_netif_ipv6_group_leave(const gnrc_netif_t *netif,
-                                              ipv6_addr_t *group)
+                                              const ipv6_addr_t *group)
 {
     assert(netif != NULL);
     assert(group != NULL);
diff --git a/sys/include/net/nanocoap.h b/sys/include/net/nanocoap.h
index fc857ad05c..73f51fe8ff 100644
--- a/sys/include/net/nanocoap.h
+++ b/sys/include/net/nanocoap.h
@@ -1069,10 +1069,7 @@ bool coap_has_unprocessed_critical_options(const coap_pkt_t *pkt);
  *
  * @returns     SZX value decoded to bytes
  */
-static inline unsigned coap_szx2size(unsigned szx)
-{
-    return (1 << (szx + 4));
-}
+#define coap_szx2size(szx) (1U << ((szx) + 4))
 
 /**
  * @brief   Helper to encode byte size into next equal or smaller SZX value