diff --git a/client/cmdflashmem.c b/client/cmdflashmem.c
index 28f0d6853..b77161951 100644
--- a/client/cmdflashmem.c
+++ b/client/cmdflashmem.c
@@ -212,7 +212,7 @@ static int CmdFlashMemLoad(const char *Cmd) {
     switch (d) {
         case DICTIONARY_MIFARE:
             start_index = DEFAULT_MF_KEYS_OFFSET;
-            res = loadFileDICTIONARY(filename, "dic", data + 2, &datalen, 6, &keycount);
+            res = loadFileDICTIONARY(filename, data + 2, &datalen, 6, &keycount);
             if (res || !keycount) {
                 free(data);
                 return 1;
@@ -223,7 +223,7 @@ static int CmdFlashMemLoad(const char *Cmd) {
             break;
         case DICTIONARY_T55XX:
             start_index = DEFAULT_T55XX_KEYS_OFFSET;
-            res = loadFileDICTIONARY(filename, "dic", data + 2, &datalen, 4, &keycount);
+            res = loadFileDICTIONARY(filename, data + 2, &datalen, 4, &keycount);
             if (res || !keycount) {
                 free(data);
                 return 1;
@@ -234,7 +234,7 @@ static int CmdFlashMemLoad(const char *Cmd) {
             break;
         case DICTIONARY_ICLASS:
             start_index = DEFAULT_ICLASS_KEYS_OFFSET;
-            res = loadFileDICTIONARY(filename, "dic", data + 2, &datalen, 8, &keycount);
+            res = loadFileDICTIONARY(filename, data + 2, &datalen, 8, &keycount);
             if (res || !keycount) {
                 free(data);
                 return 1;
@@ -244,8 +244,8 @@ static int CmdFlashMemLoad(const char *Cmd) {
             datalen += 2;
             break;
         case DICTIONARY_NONE:
-            res = loadFile(filename, "bin", data, FLASH_MEM_MAX_SIZE, &datalen);
-            //int res = loadFileEML( filename, "eml", data, &datalen);
+            res = loadFile(filename, ".bin", data, FLASH_MEM_MAX_SIZE, &datalen);
+            //int res = loadFileEML( filename, data, &datalen);
             if (res) {
                 free(data);
                 return 1;
diff --git a/client/cmdhfmf.c b/client/cmdhfmf.c
index 8471ff45a..db1b7d798 100644
--- a/client/cmdhfmf.c
+++ b/client/cmdhfmf.c
@@ -2584,8 +2584,8 @@ int CmdHF14AMfELoad(const char *Cmd) {
 
     uint8_t *data = calloc(4096, sizeof(uint8_t));
     size_t datalen = 0;
-    //int res = loadFile(filename, "bin", data, maxdatalen, &datalen);
-    int res = loadFileEML(filename, "eml", data, &datalen);
+    //int res = loadFile(filename, ".bin", data, maxdatalen, &datalen);
+    int res = loadFileEML(filename, data, &datalen);
     if (res) {
         free(data);
         return 1;
@@ -2880,12 +2880,12 @@ static int CmdHF14AMfCLoad(const char *Cmd) {
     size_t datalen = 0;
     int res = 0;
     if (fillFromBin) {
-        res = loadFile(fileName, "bin", data, maxdatalen, &datalen);
+        res = loadFile(fileName, ".bin", data, maxdatalen, &datalen);
     } else {
         if (fillFromJson) {
-            res = loadFileJSON(fileName, "json", data, maxdatalen, &datalen);
+            res = loadFileJSON(fileName, data, maxdatalen, &datalen);
         } else {
-            res = loadFileEML(Cmd, "eml", data, &datalen);
+            res = loadFileEML(Cmd, data, &datalen);
         }
     }
 
diff --git a/client/cmdlfhitag.c b/client/cmdlfhitag.c
index e7eaea6dd..f901a042c 100644
--- a/client/cmdlfhitag.c
+++ b/client/cmdlfhitag.c
@@ -295,7 +295,7 @@ static int CmdLFHitagSim(const char *Cmd) {
                 break;
             case 'e':
                 param_getstr(Cmd, cmdp + 1, filename, sizeof(filename));
-                res = loadFileEML(filename, "eml", data, &datalen);
+                res = loadFileEML(filename, data, &datalen);
                 if (res > 0 || datalen != maxdatalen) {
                     PrintAndLogDevice(FAILED, "error, bytes read mismatch file size");
                     errors = true;
@@ -306,7 +306,7 @@ static int CmdLFHitagSim(const char *Cmd) {
                 break;
             case 'j':
                 param_getstr(Cmd, cmdp + 1, filename, sizeof(filename));
-                res = loadFileJSON(filename, "json", data, maxdatalen, &datalen);
+                res = loadFileJSON(filename, data, maxdatalen, &datalen);
                 if (res > 0) {
                     errors = true;
                     break;
@@ -316,7 +316,7 @@ static int CmdLFHitagSim(const char *Cmd) {
                 break;
             case 'b':
                 param_getstr(Cmd, cmdp + 1, filename, sizeof(filename));
-                res = loadFile(filename, "bin", data, maxdatalen, &datalen);
+                res = loadFile(filename, ".bin", data, maxdatalen, &datalen);
                 if (res > 0) {
                     errors = true;
                     break;
@@ -611,7 +611,7 @@ static int CmdLFHitagCheckChallenges(const char *Cmd) {
                 return usage_hitag_checkchallenges();
             case 'f':
                 param_getstr(Cmd, cmdp + 1, filename, sizeof(filename));
-                res = loadFile(filename, "cc", data, 8 * 60, &datalen);
+                res = loadFile(filename, ".cc", data, 8 * 60, &datalen);
                 if (res > 0) {
                     errors = true;
                     break;
diff --git a/client/cmdlft55xx.c b/client/cmdlft55xx.c
index 6934e20e3..52abba90b 100644
--- a/client/cmdlft55xx.c
+++ b/client/cmdlft55xx.c
@@ -1906,7 +1906,7 @@ static int CmdT55xxChkPwds(const char *Cmd) {
             return 1;
         }
 
-        int res = loadFileDICTIONARY(filename, "dic", keyBlock, &datalen, 4, &keycount);
+        int res = loadFileDICTIONARY(filename, keyBlock, &datalen, 4, &keycount);
         if (res || keycount == 0) {
             PrintAndLogEx(WARNING, "No keys found in file");
             free(keyBlock);
diff --git a/client/loclass/fileutils.c b/client/loclass/fileutils.c
index 52be1d4b8..5370c0c5b 100644
--- a/client/loclass/fileutils.c
+++ b/client/loclass/fileutils.c
@@ -274,14 +274,11 @@ out:
 
 int loadFile(const char *preferredName, const char *suffix, void *data, size_t maxdatalen, size_t *datalen) {
 
-    if (preferredName == NULL) return 1;
-    if (suffix == NULL) return 1;
     if (data == NULL) return 1;
+    char *fileName = filenamemcopy(preferredName, suffix);
+    if (fileName == NULL) return 1;
 
     int retval = 0;
-    int size = sizeof(char) * (strlen(preferredName) + strlen(suffix) + 10);
-    char *fileName = calloc(size, sizeof(char));
-    sprintf(fileName, "%s.%s", preferredName, suffix);
 
     FILE *f = fopen(fileName, "rb");
     if (!f) {
@@ -336,17 +333,14 @@ out:
     return retval;
 }
 
-int loadFileEML(const char *preferredName, const char *suffix, void *data, size_t *datalen) {
+int loadFileEML(const char *preferredName, void *data, size_t *datalen) {
 
-    if (preferredName == NULL) return 1;
-    if (suffix == NULL) return 1;
     if (data == NULL) return 1;
+    char *fileName = filenamemcopy(preferredName, ".eml");
+    if (fileName == NULL) return 1;
 
     size_t counter = 0;
     int retval = 0, hexlen = 0;
-    int size = sizeof(char) * (strlen(preferredName) + strlen(suffix) + 10);
-    char *fileName = calloc(size, sizeof(char));
-    sprintf(fileName, "%s.%s", preferredName, suffix);
 
     FILE *f = fopen(fileName, "r");
     if (!f) {
@@ -393,20 +387,17 @@ out:
     return retval;
 }
 
-int loadFileJSON(const char *preferredName, const char *suffix, void *data, size_t maxdatalen, size_t *datalen) {
+int loadFileJSON(const char *preferredName, void *data, size_t maxdatalen, size_t *datalen) {
 
-    if (preferredName == NULL) return 1;
-    if (suffix == NULL) return 1;
     if (data == NULL) return 1;
+    char *fileName = filenamemcopy(preferredName, ".json");
+    if (fileName == NULL) return 1;
 
     *datalen = 0;
     json_t *root;
     json_error_t error;
 
     int retval = 0;
-    int size = sizeof(char) * (strlen(preferredName) + strlen(suffix) + 10);
-    char *fileName = calloc(size, sizeof(char));
-    sprintf(fileName, "%s.%s", preferredName, suffix);
 
     root = json_load_file(fileName, 0, &error);
     if (!root) {
@@ -502,11 +493,12 @@ out:
     return retval;
 }
 
-int loadFileDICTIONARY(const char *preferredName, const char *suffix, void *data, size_t *datalen, uint8_t keylen, uint16_t *keycnt) {
+int loadFileDICTIONARY(const char *preferredName, void *data, size_t *datalen, uint8_t keylen, uint16_t *keycnt) {
+
 
-    if (preferredName == NULL) return 1;
-    if (suffix == NULL) return 1;
     if (data == NULL) return 1;
+    char *fileName = filenamemcopy(preferredName, ".dic");
+    if (fileName == NULL) return 1;
 
     // t5577 == 4bytes
     // mifare == 6 bytes
@@ -523,9 +515,6 @@ int loadFileDICTIONARY(const char *preferredName, const char *suffix, void *data
 
     size_t counter = 0;
     int retval = 0;
-    int size = sizeof(char) * (strlen(preferredName) + strlen(suffix) + 10);
-    char *fileName = calloc(size, sizeof(char));
-    sprintf(fileName, "%s.%s", preferredName, suffix);
 
     FILE *f = fopen(fileName, "r");
     if (!f) {
diff --git a/client/loclass/fileutils.h b/client/loclass/fileutils.h
index 57dfbebc8..6f6b5456a 100644
--- a/client/loclass/fileutils.h
+++ b/client/loclass/fileutils.h
@@ -110,7 +110,7 @@ int saveFileJSON(const char *preferredName, const char *suffix, JSONFileType fty
  * E.g. dumpdata-15.bin
  *
  * @param preferredName
- * @param suffix the file suffix. Leave out the ".".
+ * @param suffix the file suffix. Including the ".".
  * @param data The data array to store the loaded bytes from file
  * @param maxdatalen the number of bytes that your data array has
  * @param datalen the number of bytes loaded from file
@@ -123,25 +123,23 @@ int loadFile(const char *preferredName, const char *suffix, void *data, size_t m
  * E.g. dumpdata-15.txt
  *
  * @param preferredName
- * @param suffix the file suffix. Leave out the ".".
  * @param data The data array to store the loaded bytes from file
  * @param datalen the number of bytes loaded from file
  * @return 0 for ok, 1 for failz
 */
-int loadFileEML(const char *preferredName, const char *suffix, void *data, size_t *datalen);
+int loadFileEML(const char *preferredName, void *data, size_t *datalen);
 
 /**
  * @brief  Utility function to load data from a JSON textfile. This method takes a preferred name.
  * E.g. dumpdata-15.json
  *
  * @param preferredName
- * @param suffix the file suffix. Leave out the ".".
  * @param data The data array to store the loaded bytes from file
  * @param maxdatalen maximum size of data array in bytes
  * @param datalen the number of bytes loaded from file
  * @return 0 for ok, 1 for failz
 */
-int loadFileJSON(const char *preferredName, const char *suffix, void *data, size_t maxdatalen, size_t *datalen);
+int loadFileJSON(const char *preferredName, void *data, size_t maxdatalen, size_t *datalen);
 
 
 /**
@@ -149,14 +147,13 @@ int loadFileJSON(const char *preferredName, const char *suffix, void *data, size
  * E.g. default_keys.dic
  *
  * @param preferredName
- * @param suffix the file suffix. Leave out the ".".
  * @param data The data array to store the loaded bytes from file
  * @param maxdatalen maximum size of data array in bytes
  * @param datalen the number of bytes loaded from file
  * @param keylen  the number of bytes a key per row is
  * @return 0 for ok, 1 for failz
 */
-int loadFileDICTIONARY(const char *preferredName, const char *suffix, void *data, size_t *datalen, uint8_t keylen, uint16_t *keycnt);
+int loadFileDICTIONARY(const char *preferredName, void *data, size_t *datalen, uint8_t keylen, uint16_t *keycnt);
 
 /**
  * @brief  Utility function to check and convert old mfu dump format to new
diff --git a/client/util.c b/client/util.c
index 472b9d17d..0d8781619 100644
--- a/client/util.c
+++ b/client/util.c
@@ -891,10 +891,23 @@ void str_lower(char *s) {
     for (size_t i = 0; i < strlen(s); i++)
         s[i] = tolower(s[i]);
 }
+
+// check for prefix in string
 bool str_startswith(const char *s,  const char *pre) {
     return strncmp(pre, s, strlen(pre)) == 0;
 }
 
+// check for suffix in string
+bool str_endswith(const char *s,  const char *suffix) {
+    size_t ls = strlen(s);
+    size_t lsuffix = strlen(suffix);
+    if (ls >= lsuffix)
+    {
+        return strncmp(suffix, s + (ls - lsuffix), lsuffix) == 0;
+    }
+    return false;
+}
+
 // Replace unprintable characters with a dot in char buffer
 void clean_ascii(unsigned char *buf, size_t len) {
     for (size_t i = 0; i < len; i++) {
@@ -917,7 +930,7 @@ void strcreplace(char *buf, size_t len, char from, char to) {
     }
 }
 
-char *strmcopy(char *buf) {
+char *strmcopy(const char *buf) {
     char *str = (char *) calloc(strlen(buf) + 1, sizeof(uint8_t));
     if (str != NULL) {
         memset(str, 0, strlen(buf) + 1);
@@ -925,3 +938,16 @@ char *strmcopy(char *buf) {
     }
     return str;
 }
+
+char *filenamemcopy(const char *preferredName, const char *suffix) {
+    if (preferredName == NULL) return NULL;
+    if (suffix == NULL) return NULL;
+    char *fileName = (char *) calloc(strlen(preferredName) + strlen(suffix) + 1, sizeof(uint8_t));
+    if (fileName == NULL)
+        return NULL;
+    strcpy(fileName, preferredName);
+    if (str_endswith(fileName, suffix))
+        return fileName;
+    strcat(fileName, suffix);
+    return fileName;
+}
diff --git a/client/util.h b/client/util.h
index 5e60868bb..6d0cc98aa 100644
--- a/client/util.h
+++ b/client/util.h
@@ -261,8 +261,10 @@ int num_CPUs(void); // number of logical CPUs
 
 void str_lower(char *s); // converts string to lower case
 bool str_startswith(const char *s,  const char *pre);  // check for prefix in string
+bool str_endswith(const char *s,  const char *suffix);    // check for suffix in string
 void clean_ascii(unsigned char *buf, size_t len);
 void strcleanrn(char *buf, size_t len);
 void strcreplace(char *buf, size_t len, char from, char to);
-char *strmcopy(char *buf);
+char *strmcopy(const char *buf);
+char *filenamemcopy(const char *preferredName, const char *suffix);
 #endif