diff --git a/flags.c b/flags.c
index 553daa71adc..2f7abfb7bc1 100644
--- a/flags.c
+++ b/flags.c
@@ -119,11 +119,11 @@ str bitmask_to_flag_list(enum flag_type type, int bitmask)
 	return ret;
 }
 
-int flag_list_to_bitmask(str *flags, enum flag_type type, char delim)
+int flag_list_to_bitmask(const str_const *flags, enum flag_type type, char delim)
 {
-	char *p, *lim;
-	char *crt_flag;
-	str name;
+	const char *p, *lim;
+	const char *crt_flag;
+	str_const name;
 	struct flag_entry *e;
 	int ret = 0;
 
diff --git a/flags.h b/flags.h
index 5c98b0e1e19..dd894cdba15 100644
--- a/flags.h
+++ b/flags.h
@@ -80,7 +80,7 @@ str bitmask_to_flag_list(enum flag_type type, int bitmask);
  * Note: flags which are not used at script level and are not instantiated with
  * get_flag_id_by_name will be ignored
  */
-int flag_list_to_bitmask(str *flags, enum flag_type type, char delim);
+int flag_list_to_bitmask(const str_const *flags, enum flag_type type, char delim);
 
 unsigned int fixup_flag(int flag_type, const str *flag_name);
 int get_flag_id_by_name(int flag_type, char *flag_name, int flag_name_len);
diff --git a/modules/usrloc/dlist.c b/modules/usrloc/dlist.c
index 1c2af0b9eb8..f7f20fe6985 100644
--- a/modules/usrloc/dlist.c
+++ b/modules/usrloc/dlist.c
@@ -122,7 +122,6 @@ static int get_domain_db_ucontacts(udomain_t *d, void *buf, int *len,
 	db_res_t *res = NULL;
 	db_row_t *row;
 	db_val_t *val;
-	str flag_list;
 	int i, no_rows = 10;
 	time_t now;
 	char *p, *p1;
@@ -199,9 +198,10 @@ static int get_domain_db_ucontacts(udomain_t *d, void *buf, int *len,
 
 	do {
 		for (i = 0; i < RES_ROW_N(res); i++) {
+			str_const flag_list;
 			row = RES_ROWS(res) + i;
 			val = ROW_VALUES(row) + 3; /* cflags */
-			flag_list.s   = (char *)VAL_STRING(val);
+			flag_list.s   = VAL_STRING(val);
 			flag_list.len = flag_list.s ? strlen(flag_list.s) : 0;
 
 			LM_DBG("contact cflags: '%.*s'\n", flag_list.len, flag_list.s);
@@ -427,7 +427,7 @@ cdb_pack_ping_data(const str *aor, const cdb_pair_t *contact,
 				break;
 
 			case 'f':
-				cflags = flag_list_to_bitmask(&pair->val.val.st,
+				cflags = flag_list_to_bitmask(str2const(&pair->val.val.st),
 				                              FLAG_TYPE_BRANCH, FLAG_DELIM);
 				cols_needed &= ~COL_CFLAGS;
 				break;
diff --git a/modules/usrloc/udomain.c b/modules/usrloc/udomain.c
index c482a74be72..f848a900745 100644
--- a/modules/usrloc/udomain.c
+++ b/modules/usrloc/udomain.c
@@ -190,7 +190,7 @@ cdb_ctdict2info(const cdb_dict_t *ct_fields, str *contact)
 				ci.callid = &callid;
 				break;
 			case 'f':
-				ci.cflags = flag_list_to_bitmask(&pair->val.val.st,
+				ci.cflags = flag_list_to_bitmask(str2const(&pair->val.val.st),
 				                                 FLAG_TYPE_BRANCH, FLAG_DELIM);
 				break;
 			case 'o':
@@ -271,7 +271,7 @@ static inline ucontact_info_t* dbrow2info(db_val_t *vals, str *contact)
 {
 	static ucontact_info_t ci;
 	static str callid, ua, received, host, path, instance;
-	static str attr, packed_kv, flags;
+	static str attr, packed_kv;
 	int port, proto;
 	char *p;
 
@@ -323,7 +323,8 @@ static inline ucontact_info_t* dbrow2info(db_val_t *vals, str *contact)
 	ci.flags  = VAL_BITMAP(vals+6);
 
 	if (!VAL_NULL(vals+7)) {
-		flags.s   = (char *)VAL_STRING(vals+7);
+		str_const flags;
+		flags.s   = VAL_STRING(vals+7);
 		flags.len = strlen(flags.s);
 		LM_DBG("flag str: '%.*s'\n", flags.len, flags.s);
 
diff --git a/pvar.c b/pvar.c
index 3fa93337c8e..5e1f4fa89c6 100644
--- a/pvar.c
+++ b/pvar.c
@@ -3243,7 +3243,7 @@ static int pv_set_branch_fields(struct sip_msg* msg, pv_param_t *param,
 				return -1;
 			}
 			flags = (!val||val->flags&PV_VAL_NULL)?
-				0 : flag_list_to_bitmask(&val->rs, FLAG_TYPE_BRANCH, FLAG_DELIM);
+				0 : flag_list_to_bitmask(str2const(&val->rs), FLAG_TYPE_BRANCH, FLAG_DELIM);
 			return update_branch( idx, NULL, NULL,
 				NULL, NULL, &flags, NULL);
 		case BR_SOCKET_ID: /* set SOCKET */