diff --git a/src/include/lwip/snmp_asn1.h b/src/include/lwip/snmp_asn1.h
index 147f5db9..b05c8e72 100644
--- a/src/include/lwip/snmp_asn1.h
+++ b/src/include/lwip/snmp_asn1.h
@@ -90,7 +90,7 @@ err_t snmp_asn1_enc_length(struct pbuf *p, u16_t ofs, u16_t length);
 err_t snmp_asn1_enc_u32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, u32_t value);
 err_t snmp_asn1_enc_s32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, s32_t value);
 err_t snmp_asn1_enc_oid(struct pbuf *p, u16_t ofs, u8_t ident_len, const s32_t *ident);
-err_t snmp_asn1_enc_raw(struct pbuf *p, u16_t ofs, u16_t raw_len, const u8_t *raw);
+err_t snmp_asn1_enc_raw(struct pbuf *p, u16_t ofs, u16_t raw_len, u8_t *raw);
 
 #ifdef __cplusplus
 }
diff --git a/src/include/lwip/snmp_structs.h b/src/include/lwip/snmp_structs.h
index 87786cfb..b735c71e 100644
--- a/src/include/lwip/snmp_structs.h
+++ b/src/include/lwip/snmp_structs.h
@@ -138,7 +138,7 @@ struct mib_array_node
 
   /* additional struct members */
   const s32_t *objid;
-  const struct mib_node* const *nptr;
+  struct mib_node* const *nptr;
 };
 
 /** derived node, points to a fixed size mem_malloced array
@@ -254,8 +254,8 @@ s8_t snmp_mib_node_insert(struct mib_list_rootnode *rn, s32_t objid, struct mib_
 s8_t snmp_mib_node_find(struct mib_list_rootnode *rn, s32_t objid, struct mib_list_node **fn);
 struct mib_list_rootnode *snmp_mib_node_delete(struct mib_list_rootnode *rn, struct mib_list_node *n);
 
-struct mib_node* snmp_search_tree(const struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_name_ptr *np);
-struct mib_node* snmp_expand_tree(const struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret);
+struct mib_node* snmp_search_tree(struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_name_ptr *np);
+struct mib_node* snmp_expand_tree(struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret);
 u8_t snmp_iso_prefix_tst(u8_t ident_len, s32_t *ident);
 u8_t snmp_iso_prefix_expand(u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret);