diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7b34aa61d..3f0253e58 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@ All notable changes to this project will be documented in this file.
 This project uses the changelog in accordance with [keepchangelog](http://keepachangelog.com/). Please use this to write notable changes, which is not the same as git commit log...
 
 ## [unreleased][unreleased]
+ - Fixed `data asn1` - now handles bad input better (@iceman1001)
  - Added new public key for signature MIFARE Plus Troika (@iceman100)
  - Fixed the client build on Android (@wh201906)
  - Added TCP connection support on Windows (@wh201906)
diff --git a/client/src/cmdpiv.c b/client/src/cmdpiv.c
index 4d23a9b4b..8264c5936 100644
--- a/client/src/cmdpiv.c
+++ b/client/src/cmdpiv.c
@@ -576,7 +576,8 @@ static int PivGetData(Iso7816CommandChannel channel, const uint8_t tag[], size_t
                 struct tlvdb_root *new_root = realloc(root, sizeof(*root) + capacity);
                 if (new_root == NULL) {
                     PrintAndLogEx(FAILED, "Running out of memory while re-allocating buffer");
-                    free(root);
+                    //free(root);
+                    tlvdb_root_free(root);
                     return PM3_EMALLOC;
                 }
                 root = new_root;
diff --git a/client/src/emv/emvcore.c b/client/src/emv/emvcore.c
index fbc59b1c0..0628fcf76 100644
--- a/client/src/emv/emvcore.c
+++ b/client/src/emv/emvcore.c
@@ -177,7 +177,7 @@ bool TLVPrintFromBuffer(uint8_t *data, int datalen) {
 }
 
 void TLVPrintFromTLVLev(struct tlvdb *tlv, int level) {
-    if (!tlv)
+    if (tlv == NULL)
         return;
 
     tlvdb_visit(tlv, emv_print_cb, NULL, level);
@@ -193,15 +193,16 @@ void TLVPrintAIDlistFromSelectTLV(struct tlvdb *tlv) {
     PrintAndLogEx(INFO, "|------------------+--------+-------------------------|");
 
     struct tlvdb *ttmp = tlvdb_find(tlv, 0x6f);
-    if (!ttmp)
+    if (ttmp == NULL)
         PrintAndLogEx(INFO, "|                         none                        |");
 
     while (ttmp) {
         const struct tlv *tgAID = tlvdb_get_inchild(ttmp, 0x84, NULL);
         const struct tlv *tgName = tlvdb_get_inchild(ttmp, 0x50, NULL);
         const struct tlv *tgPrio = tlvdb_get_inchild(ttmp, 0x87, NULL);
-        if (!tgAID)
+        if (!tgAID) {
             break;
+        }
         PrintAndLogEx(INFO, "| %s|   %s  | %s|",
                       sprint_hex_inrow_ex(tgAID->value, tgAID->len, 17),
                       (tgPrio) ? sprint_hex(tgPrio->value, 1) : "   ",
diff --git a/client/src/emv/tlv.c b/client/src/emv/tlv.c
index 67fa51b58..f025fbe27 100644
--- a/client/src/emv/tlv.c
+++ b/client/src/emv/tlv.c
@@ -197,9 +197,7 @@ struct tlvdb *tlvdb_parse(const unsigned char *buf, size_t len) {
     return &root->db;
 
 err:
-    tlvdb_free(&root->db);
-
-    free(root);
+    tlvdb_root_free(root);
     return NULL;
 }
 
@@ -208,22 +206,32 @@ struct tlvdb *tlvdb_parse_multi(const unsigned char *buf, size_t len) {
     const unsigned char *tmp;
     size_t left;
 
-    if (!len || !buf)
+    if (len == 0 || buf == NULL) {
         return NULL;
+    }
 
     root = calloc(1, sizeof(*root) + len);
+    if (root == NULL) {
+        return NULL;
+    }
+
     root->len = len;
     memcpy(root->buf, buf, len);
 
     tmp = root->buf;
     left = len;
 
-    if (!tlvdb_parse_one(&root->db, NULL, &tmp, &left))
+    if (tlvdb_parse_one(&root->db, NULL, &tmp, &left) == false) {
         goto err;
+    }
 
     while (left != 0) {
         struct tlvdb *db = calloc(1, sizeof(*db));
-        if (!tlvdb_parse_one(db, NULL, &tmp, &left)) {
+        if (db == NULL ) {
+            goto err;
+        }
+
+        if (tlvdb_parse_one(db, NULL, &tmp, &left) == false) {
             free(db);
             goto err;
         }
@@ -234,9 +242,7 @@ struct tlvdb *tlvdb_parse_multi(const unsigned char *buf, size_t len) {
     return &root->db;
 
 err:
-    tlvdb_free(&root->db);
-
-    free(root);
+    tlvdb_root_free(root);
     return NULL;
 }
 
@@ -313,8 +319,9 @@ struct tlvdb *tlvdb_external(tlv_tag_t tag, size_t len, const unsigned char *val
 void tlvdb_free(struct tlvdb *tlvdb) {
     struct tlvdb *next = NULL;
 
-    if (!tlvdb)
+    if (tlvdb == NULL) {
         return;
+    }
 
     for (; tlvdb; tlvdb = next) {
         next = tlvdb->next;
@@ -339,36 +346,42 @@ void tlvdb_root_free(struct tlvdb_root *root) {
 }
 
 struct tlvdb *tlvdb_find_next(struct tlvdb *tlvdb, tlv_tag_t tag) {
-    if (!tlvdb)
+    if (tlvdb == NULL) {
         return NULL;
+    }
 
     return tlvdb_find(tlvdb->next, tag);
 }
 
 struct tlvdb *tlvdb_find(struct tlvdb *tlvdb, tlv_tag_t tag) {
-    if (!tlvdb)
+    if (tlvdb == NULL) {
         return NULL;
+    }
 
     for (; tlvdb; tlvdb = tlvdb->next) {
-        if (tlvdb->tag.tag == tag)
+        if (tlvdb->tag.tag == tag) {
             return tlvdb;
+        }
     }
 
     return NULL;
 }
 
 struct tlvdb *tlvdb_find_full(struct tlvdb *tlvdb, tlv_tag_t tag) {
-    if (!tlvdb)
+    if (tlvdb == NULL) {
         return NULL;
+    }
 
     for (; tlvdb; tlvdb = tlvdb->next) {
-        if (tlvdb->tag.tag == tag)
+        if (tlvdb->tag.tag == tag) {
             return tlvdb;
+        }
 
         if (tlvdb->children) {
             struct tlvdb *ch = tlvdb_find_full(tlvdb->children, tag);
-            if (ch)
+            if (ch) {
                 return ch;
+            }
         }
     }
 
@@ -391,12 +404,14 @@ struct tlvdb *tlvdb_find_path(struct tlvdb *tlvdb, tlv_tag_t tag[]) {
 }
 
 void tlvdb_add(struct tlvdb *tlvdb, struct tlvdb *other) {
-    if (tlvdb == other)
+    if (tlvdb == other) {
         return;
+    }
 
     while (tlvdb->next) {
-        if (tlvdb->next == other)
+        if (tlvdb->next == other) {
             return;
+        }
 
         tlvdb = tlvdb->next;
     }
@@ -405,17 +420,21 @@ void tlvdb_add(struct tlvdb *tlvdb, struct tlvdb *other) {
 }
 
 void tlvdb_change_or_add_node_ex(struct tlvdb *tlvdb, tlv_tag_t tag, size_t len, const unsigned char *value, struct tlvdb **tlvdb_elm) {
+
     struct tlvdb *telm = tlvdb_find_full(tlvdb, tag);
     if (telm == NULL) {
         // new tlv element
         struct tlvdb *elm = tlvdb_fixed(tag, len, value);
         tlvdb_add(tlvdb, elm);
-        if (tlvdb_elm)
+        if (tlvdb_elm) {
             *tlvdb_elm = elm;
+        }
+
     } else {
         // the same tlv structure
-        if (telm->tag.tag == tag && telm->tag.len == len && !memcmp(telm->tag.value, value, len))
+        if (telm->tag.tag == tag && telm->tag.len == len && !memcmp(telm->tag.value, value, len)) {
             return;
+        }
 
         // replace tlv element
         struct tlvdb *tnewelm = tlvdb_fixed(tag, len, value);
@@ -434,8 +453,9 @@ void tlvdb_change_or_add_node_ex(struct tlvdb *tlvdb, tlv_tag_t tag, size_t len,
             // elm in root
             struct tlvdb *celm = tlvdb;
             // elm in child list of node
-            if (telm->parent && telm->parent->children)
+            if (telm->parent && telm->parent->children) {
                 celm = telm->parent->children;
+            }
 
             // find previous element
             for (; celm; celm = celm->next) {
@@ -455,7 +475,8 @@ void tlvdb_change_or_add_node_ex(struct tlvdb *tlvdb, tlv_tag_t tag, size_t len,
             *tlvdb_elm = tnewelm;
             tnewelm_linked = true;
         }
-        if (! tnewelm_linked) {
+
+        if (!tnewelm_linked) {
             tlvdb_free(tnewelm);
         }
     }
@@ -470,8 +491,9 @@ void tlvdb_change_or_add_node(struct tlvdb *tlvdb, tlv_tag_t tag, size_t len, co
 void tlvdb_visit(const struct tlvdb *tlvdb, tlv_cb cb, void *data, int level) {
     struct tlvdb *next = NULL;
 
-    if (!tlvdb)
+    if (tlvdb == NULL) {
         return;
+    }
 
     for (; tlvdb; tlvdb = next) {
         next = tlvdb->next;
@@ -481,12 +503,14 @@ void tlvdb_visit(const struct tlvdb *tlvdb, tlv_cb cb, void *data, int level) {
 }
 
 static const struct tlvdb *tlvdb_next(const struct tlvdb *tlvdb) {
-    if (tlvdb->children)
+    if (tlvdb->children) {
         return tlvdb->children;
+    }
 
     while (tlvdb) {
-        if (tlvdb->next)
+        if (tlvdb->next) {
             return tlvdb->next;
+        }
 
         tlvdb = tlvdb->parent;
     }
@@ -502,8 +526,9 @@ const struct tlv *tlvdb_get(const struct tlvdb *tlvdb, tlv_tag_t tag, const stru
 
 
     while (tlvdb) {
-        if (tlvdb->tag.tag == tag)
+        if (tlvdb->tag.tag == tag) {
             return &tlvdb->tag;
+        }
 
         tlvdb = tlvdb_next(tlvdb);
     }
@@ -570,11 +595,13 @@ bool tlv_is_constructed(const struct tlv *tlv) {
 }
 
 bool tlv_equal(const struct tlv *a, const struct tlv *b) {
-    if (!a && !b)
+    if (a == NULL && b == NULL) {
         return true;
+    }
 
-    if (!a || !b)
+    if (a == NULL || b == NULL) {
         return false;
+    }
 
     return a->tag == b->tag && a->len == b->len && !memcmp(a->value, b->value, a->len);
 }
@@ -599,8 +626,9 @@ bool tlvdb_get_uint8(struct tlvdb *tlvRoot, tlv_tag_t tag, uint8_t *value) {
 bool tlv_get_uint8(const struct tlv *etlv, uint8_t *value) {
     *value = 0;
     if (etlv) {
-        if (etlv->len == 0)
+        if (etlv->len == 0) {
             return true;
+        }
 
         if (etlv->len == 1) {
             *value = etlv->value[0];
@@ -613,8 +641,9 @@ bool tlv_get_uint8(const struct tlv *etlv, uint8_t *value) {
 bool tlv_get_int(const struct tlv *etlv, int *value) {
     *value = 0;
     if (etlv) {
-        if (etlv->len == 0)
+        if (etlv->len == 0) {
             return true;
+        }
 
         if (etlv->len <= 4) {
             for (int i = 0; i < etlv->len; i++) {