diff --git a/client/src/fileutils.c b/client/src/fileutils.c
index 9545753bc..5fa74c4b0 100644
--- a/client/src/fileutils.c
+++ b/client/src/fileutils.c
@@ -747,7 +747,7 @@ out:
 int saveFileJSONroot(const char *preferredName, void *root, size_t flags, bool verbose) {
     return saveFileJSONrootEx(preferredName, root, flags, verbose, false);
 }
-int saveFileJSONrootEx(const char *preferredName, void *root, size_t flags, bool verbose, bool overwrite) {
+int saveFileJSONrootEx(const char *preferredName, const void *root, size_t flags, bool verbose, bool overwrite) {
     if (root == NULL)
         return PM3_EINVARG;
 
@@ -863,7 +863,7 @@ out:
 }
 
 // key file dump
-int createMfcKeyDump(const char *preferredName, uint8_t sectorsCnt, sector_t *e_sector) {
+int createMfcKeyDump(const char *preferredName, uint8_t sectorsCnt, const sector_t *e_sector) {
 
     if (e_sector == NULL) return PM3_EINVARG;
 
@@ -1743,7 +1743,7 @@ int loadFileJSONex(const char *preferredName, void *data, size_t maxdatalen, siz
                 goto out;
             }
 
-            snprintf(blocks, sizeof(blocks), "$.blocks.%d", i);
+            snprintf(blocks, sizeof(blocks), "$.blocks.%u", i);
             JsonLoadBufAsHex(root, blocks, &tag->data[sptr], 4, &len);
             if (load_file_sanity(ctype, tag->bytesPerPage, i, len) == false) {
                 break;
@@ -1790,7 +1790,7 @@ int loadFileJSONex(const char *preferredName, void *data, size_t maxdatalen, siz
                 goto out;
             }
 
-            snprintf(blocks, sizeof(blocks), "$.blocks.%d", i);
+            snprintf(blocks, sizeof(blocks), "$.blocks.%u", i);
             JsonLoadBufAsHex(root, blocks, &tag->data[sptr], 8, &len);
             if (load_file_sanity(ctype, tag->bytesPerPage, i, len) == false) {
                 break;
@@ -2426,7 +2426,7 @@ mfu_df_e detect_mfu_dump_format(uint8_t **dump, bool verbose) {
 
     // detect plain
     if (retval == MFU_DF_UNKNOWN) {
-        uint8_t *plain = *dump;
+        const uint8_t *plain = *dump;
         bcc0 = ct ^ plain[0] ^ plain[1] ^ plain[2];
         bcc1 = plain[4] ^ plain[5] ^ plain[6] ^ plain[7];
         if ((bcc0 == plain[3]) && (bcc1 == plain[8])) {
diff --git a/client/src/fileutils.h b/client/src/fileutils.h
index 3eb2a0541..b469eba68 100644
--- a/client/src/fileutils.h
+++ b/client/src/fileutils.h
@@ -107,8 +107,8 @@ int fileExists(const char *filename);
 bool setDefaultPath(savePaths_t pathIndex, const char *path);
 
 char *newfilenamemcopy(const char *preferredName, const char *suffix);
-char *newfilenamemcopyEx(const char *preferredName, const char *suffix, savePaths_t save_path);
-void truncate_filename(char *fn,  uint16_t len);
+char *newfilenamemcopyEx(const char *preferredName, const char *suffix, savePaths_t e_save_path);
+void truncate_filename(char *fn,  uint16_t maxlen);
 
 
 /**
@@ -138,7 +138,7 @@ int saveFile(const char *preferredName, const char *suffix, const void *data, si
 int saveFileJSON(const char *preferredName, JSONFileType ftype, uint8_t *data, size_t datalen, void (*callback)(json_t *));
 int saveFileJSONex(const char *preferredName, JSONFileType ftype, uint8_t *data, size_t datalen, bool verbose, void (*callback)(json_t *), savePaths_t e_save_path);
 int saveFileJSONroot(const char *preferredName, void *root, size_t flags, bool verbose);
-int saveFileJSONrootEx(const char *preferredName, void *root, size_t flags, bool verbose, bool overwrite);
+int saveFileJSONrootEx(const char *preferredName, const void *root, size_t flags, bool verbose, bool overwrite);
 /** STUB
  * @brief Utility function to save WAVE data to a file. This method takes a preferred name, but if that
  * file already exists, it tries with another name until it finds something suitable.
@@ -171,7 +171,7 @@ int saveFilePM3(const char *preferredName, int *data, size_t datalen);
  * @param e_sector the keys in question
  * @return 0 for ok, 1 for failz
  */
-int createMfcKeyDump(const char *preferredName, uint8_t sectorsCnt, sector_t *e_sector);
+int createMfcKeyDump(const char *preferredName, uint8_t sectorsCnt, const sector_t *e_sector);
 
 /**
  * @brief Utility function to load data from a binary file. This method takes a preferred name.