diff --git a/MicroDexed.ino b/MicroDexed.ino
index ef83321..00f153d 100644
--- a/MicroDexed.ino
+++ b/MicroDexed.ino
@@ -2630,25 +2630,25 @@ uint8_t check_sd_cards(void)
 #endif
     switch (card.type()) {
       case SD_CARD_TYPE_SD1:
-        sprintf(sd_string, "%-5s", "SD1");
+        snprintf_P(sd_string, strlen(sd_string), PSTR("%-5s"), PSTR("SD1"));
 #ifdef DEBUG
         Serial.println(F("SD1"));
 #endif
         break;
       case SD_CARD_TYPE_SD2:
-        sprintf(sd_string, "%-5s", "SD2");
+        snprintf_P(sd_string, strlen(sd_string), PSTR("%-5s"), PSTR("SD2"));
 #ifdef DEBUG
         Serial.println(F("SD2"));
 #endif
         break;
       case SD_CARD_TYPE_SDHC:
-        sprintf(sd_string, "%-5s", "SD2");
+        snprintf_P(sd_string, strlen(sd_string), PSTR("%-5s"), PSTR("SD2"));
 #ifdef DEBUG
         Serial.println(F("SDHC"));
 #endif
         break;
       default:
-        sprintf(sd_string, "%-5s", "UKNW");
+        snprintf_P(sd_string, strlen(sd_string), PSTR("%-5s"), PSTR("UKNW"));
 #ifdef DEBUG
         Serial.println(F("Unknown"));
 #endif
@@ -2679,7 +2679,7 @@ uint8_t check_sd_cards(void)
     Serial.println(volumesize);
 #endif
 
-    sprintf(sd_string + 5, "FAT%2d %02dGB", volume.fatType(), int(volumesize));
+    snprintf_P(sd_string + 5, strlen(sd_string), PSTR("FAT%2d %02dGB"), volume.fatType(), int(volumesize));
   }
 
 #ifdef DEBUG
@@ -2702,7 +2702,7 @@ void check_and_create_directories(void)
     // create directories for banks
     for (i = 0; i < MAX_BANKS; i++)
     {
-      sprintf(tmp, "/%d", i);
+      snprintf_P(tmp, strlen(tmp), PSTR("/%d"), i);
       if (!SD.exists(tmp))
       {
 #ifdef DEBUG
@@ -2713,7 +2713,7 @@ void check_and_create_directories(void)
       }
     }
 
-    sprintf(tmp, "/%s", PERFORMANCE_CONFIG_PATH);
+    snprintf_P(tmp, strlen(tmp), PSTR("/%s"), PERFORMANCE_CONFIG_PATH);
     if (!SD.exists(tmp))
     {
 #ifdef DEBUG
@@ -2725,7 +2725,7 @@ void check_and_create_directories(void)
 
     /*
         // create directories for configuration files
-        sprintf(tmp, "/%s", VOICE_CONFIG_PATH);
+        snprintf_P(tmp, strlen(tmp), PSTR("/%s"), VOICE_CONFIG_PATH);
         if (!SD.exists(tmp))
         {
       #ifdef DEBUG
@@ -2734,7 +2734,7 @@ void check_and_create_directories(void)
       #endif
           SD.mkdir(tmp);
         }
-        sprintf(tmp, "/%s", PERFORMANCE_CONFIG_PATH);
+        snprintf_P(tmp, strlen(tmp), PSTR("/%s"), PERFORMANCE_CONFIG_PATH);
         if (!SD.exists(tmp))
         {
       #ifdef DEBUG
@@ -2743,7 +2743,7 @@ void check_and_create_directories(void)
       #endif
           SD.mkdir(tmp);
         }
-        sprintf(tmp, "/%s", FX_CONFIG_PATH);
+        snprintf_P(tmp, strlen(tmp), PSTR("/%s"), FX_CONFIG_PATH);
         if (!SD.exists(tmp))
         {
       #ifdef DEBUG
@@ -2752,7 +2752,7 @@ void check_and_create_directories(void)
       #endif
           SD.mkdir(tmp);
         }
-        sprintf(tmp, "/%s", DRUM_CONFIG_PATH);
+        snprintf_P(tmp, strlen(tmp), PSTR("/%s"), DRUM_CONFIG_PATH);
         if (!SD.exists(tmp))
         {
       #ifdef DEBUG
@@ -2761,7 +2761,7 @@ void check_and_create_directories(void)
       #endif
           SD.mkdir(tmp);
         }
-        sprintf(tmp, "/%s", FAV_CONFIG_PATH);
+        snprintf_P(tmp, strlen(tmp), PSTR("/%s"), FAV_CONFIG_PATH);
         if (!SD.exists(tmp))
         {
       #ifdef DEBUG
@@ -2772,7 +2772,7 @@ void check_and_create_directories(void)
         }
     */
 
-    sprintf(tmp, "/%s", PERFORMANCE_CONFIG_PATH);
+    snprintf_P(tmp, strlen(tmp), PSTR("/%s"), PERFORMANCE_CONFIG_PATH);
     if (!SD.exists(tmp))
     {
 #ifdef DEBUG
@@ -2783,14 +2783,14 @@ void check_and_create_directories(void)
     }
 
     //check if updated Fav-System is ready or if setup has to run once.
-    sprintf(tmp, "/%s/fav-v2", FAV_CONFIG_PATH);
+    snprintf_P(tmp, strlen(tmp), PSTR("/%s/fav-v2"), FAV_CONFIG_PATH);
     if (!SD.exists(tmp)) {
 
       // Clear now obsolte marker files from Favs.
       // Only needs to run once.
       for (uint8_t i = 0; i < MAX_BANKS; i++)
       {
-        sprintf(tmp, "/%s/%d/hasfav", FAV_CONFIG_PATH, i);
+        snprintf_P(tmp, strlen(tmp), PSTR("/%s/%d/hasfav"), FAV_CONFIG_PATH, i);
 #ifdef DEBUG
         Serial.print(F("Delete Marker File"));
         Serial.println(tmp);
@@ -2802,7 +2802,7 @@ void check_and_create_directories(void)
       // Only needs to run once.
       for (uint8_t i = 0; i < MAX_BANKS; i++)
       {
-        sprintf(tmp, "/%s/%d", FAV_CONFIG_PATH, i);
+        snprintf_P(tmp, strlen(tmp), PSTR("/%s/%d"), FAV_CONFIG_PATH, i);
 #ifdef DEBUG
         Serial.print(F("Delete empty folder "));
         Serial.println(tmp);
@@ -2810,7 +2810,7 @@ void check_and_create_directories(void)
         if (SD.exists(tmp))
           SD.rmdir(tmp);
       }
-      sprintf(tmp, "/%s/fav-v2", FAV_CONFIG_PATH);
+      snprintf_P(tmp, strlen(tmp), PSTR("/%s/fav-v2"), FAV_CONFIG_PATH);
       if (!SD.exists(tmp))
         SD.mkdir(tmp);  // Set Marker so that the Cleanup loops only run once.
     }
@@ -3087,7 +3087,7 @@ void SerialPrintFormatInt3(uint8_t num)
 {
   char buf[4];
   memset(buf, 0, 4);
-  sprintf(buf, "%3d", num);
+  snprintf_P(buf, strlen(buf), PSTR("%3d"), num);
   Serial.print(buf);
 }
 
diff --git a/dexed_sd.cpp b/dexed_sd.cpp
index 108c350..bad4255 100644
--- a/dexed_sd.cpp
+++ b/dexed_sd.cpp
@@ -83,7 +83,7 @@ bool load_sd_voice(uint8_t b, uint8_t v, uint8_t instance_id)
     uint8_t data[128];
 
     get_bank_name(b, bank_name, sizeof(bank_name));
-    sprintf(filename, "/%d/%s.syx", b, bank_name);
+    snprintf_P(filename, strlen(filename), PSTR("/%d/%s.syx"), b, bank_name);
 
     AudioNoInterrupts();
     sysex = SD.open(filename);
@@ -154,7 +154,7 @@ bool save_sd_voice(uint8_t b, uint8_t v, uint8_t instance_id)
     uint8_t data[128];
 
     get_bank_name(b, bank_name, sizeof(bank_name));
-    sprintf(filename, "/%d/%s.syx", b, bank_name);
+    snprintf_P(filename, strlen(filename), PSTR("/%d/%s.syx"), b, bank_name);
 
     AudioNoInterrupts();
     sysex = SD.open(filename, FILE_WRITE);
@@ -369,7 +369,7 @@ bool save_sd_bank(const char* bank_filename, uint8_t* data)
 
     // first remove old bank
     sscanf(bank_filename, "/%d/%s", &bank_number, tmp);
-    sprintf(tmp, "/%d", bank_number);
+    snprintf_P(tmp, strlen(tmp), PSTR("/%d"), bank_number);
     AudioNoInterrupts();
     root = SD.open(tmp);
     while (42 == 42)
@@ -385,7 +385,7 @@ bool save_sd_bank(const char* bank_filename, uint8_t* data)
           Serial.print(F("/"));
           Serial.println(entry.name());
 #endif
-          sprintf(tmp2, "%s/%s", tmp, entry.name());
+          snprintf_P(tmp2, strlen(tmp2), PSTR("%s/%s"), tmp, entry.name());
           entry.close();
 #ifndef DEBUG
           SD.remove(tmp2);
@@ -444,7 +444,7 @@ bool load_sd_drumsettings_json(uint8_t number)
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
     char filename[CONFIG_FILENAME_LEN];
 
-    sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, DRUMS_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, DRUMS_CONFIG_NAME);
 
     // first check if file exists...
     AudioNoInterrupts();
@@ -518,7 +518,7 @@ bool save_sd_drumsettings_json(uint8_t number)
 
     if (check_performance_directory(number))
     {
-      sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, DRUMS_CONFIG_NAME);
+      snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, DRUMS_CONFIG_NAME);
 
 #ifdef DEBUG
       Serial.print(F("Saving drums config "));
@@ -598,7 +598,7 @@ bool load_sd_voiceconfig_json(uint8_t vc, uint8_t instance_id)
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
 
-    sprintf(filename, "/%s/%d/%s%d.json", PERFORMANCE_CONFIG_PATH, vc, VOICE_CONFIG_NAME, instance_id + 1);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s%d.json"), PERFORMANCE_CONFIG_PATH, vc, VOICE_CONFIG_NAME, instance_id + 1);
 
     // first check if file exists...
     AudioNoInterrupts();
@@ -691,7 +691,7 @@ bool save_sd_voiceconfig_json(uint8_t vc, uint8_t instance_id)
   {
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
-    sprintf(filename, "/%s/%d/%s%d.json", PERFORMANCE_CONFIG_PATH, vc, VOICE_CONFIG_NAME, instance_id + 1);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s%d.json"), PERFORMANCE_CONFIG_PATH, vc, VOICE_CONFIG_NAME, instance_id + 1);
 
 #ifdef DEBUG
     Serial.print(F("Saving voice config "));
@@ -782,7 +782,7 @@ bool load_sd_fx_json(uint8_t number)
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
     char filename[CONFIG_FILENAME_LEN];
-    sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, FX_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, FX_CONFIG_NAME);
 
     // first check if file exists...
     AudioNoInterrupts();
@@ -882,7 +882,7 @@ bool save_sd_fx_json(uint8_t number)
   {
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
-    sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, FX_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, FX_CONFIG_NAME);
 
 #ifdef DEBUG
     Serial.print(F("Saving fx config "));
@@ -968,7 +968,7 @@ bool load_sd_epiano_json(uint8_t number)
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
     char filename[CONFIG_FILENAME_LEN];
-    sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, EPIANO_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, EPIANO_CONFIG_NAME);
 
     // first check if file exists...
     AudioNoInterrupts();
@@ -1048,7 +1048,7 @@ bool save_sd_epiano_json(uint8_t number)
   {
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
-    sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, EPIANO_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, EPIANO_CONFIG_NAME);
 
 #ifdef DEBUG
     Serial.print(F("Saving epiano config "));
@@ -1117,7 +1117,7 @@ bool load_sd_sys_json(void)
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
     char filename[CONFIG_FILENAME_LEN];
-    sprintf(filename, "/%s.json", SYS_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s.json"), SYS_CONFIG_NAME);
 
     // first check if file exists...
     AudioNoInterrupts();
@@ -1182,7 +1182,7 @@ bool save_sd_sys_json(void)
   {
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
-    sprintf(filename, "/%s.json", SYS_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s.json"), SYS_CONFIG_NAME);
 
 #ifdef DEBUG
     Serial.print(F("Saving sys config to "));
@@ -1249,7 +1249,7 @@ bool save_sd_performance_json(uint8_t number)
 
   for (uint8_t i = 0; i < MAX_DEXED; i++)
   {
-    sprintf(filename, "/%s/%d/%s%d.json", PERFORMANCE_CONFIG_PATH, number, VOICE_CONFIG_NAME, i);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s%d.json"), PERFORMANCE_CONFIG_PATH, number, VOICE_CONFIG_NAME, i);
 #ifdef DEBUG
     Serial.print(F("Write Voice-Config"));
     Serial.println(filename);
@@ -1261,7 +1261,7 @@ bool save_sd_performance_json(uint8_t number)
   {
     File json;
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
-    sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, PERFORMANCE_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, PERFORMANCE_CONFIG_NAME);
 #ifdef DEBUG
     Serial.print(F("Saving performance config "));
     Serial.print(number);
@@ -1309,7 +1309,7 @@ bool check_performance_directory(uint8_t number)
 
   if (sd_card > 0)
   {
-    sprintf(dir, "/%s/%d", PERFORMANCE_CONFIG_PATH, number);
+    snprintf_P(dir, strlen(dir), PSTR("/%s/%d"), PERFORMANCE_CONFIG_PATH, number);
 
     AudioNoInterrupts();
     SD.begin();
@@ -1353,7 +1353,7 @@ void get_sd_performance_name_json(uint8_t number)
     StaticJsonDocument<JSON_BUFFER_SIZE> data_json;
     char filename[CONFIG_FILENAME_LEN];
 
-    sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, PERFORMANCE_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, PERFORMANCE_CONFIG_NAME);
 
     // first check if file exists...
     AudioNoInterrupts();
@@ -1439,7 +1439,7 @@ bool check_sd_performance_exists(uint8_t number)
   {
     char filename[CONFIG_FILENAME_LEN];
 
-    sprintf(filename, "/%s/%d/%s.json", PERFORMANCE_CONFIG_PATH, number, PERFORMANCE_CONFIG_NAME);
+    snprintf_P(filename, strlen(filename), PSTR("/%s/%d/%s.json"), PERFORMANCE_CONFIG_PATH, number, PERFORMANCE_CONFIG_NAME);
 
     // check if file exists...
     if (SD.exists(filename))
@@ -1647,7 +1647,7 @@ bool get_bank_name(uint8_t b, char* name, uint8_t len)
 
     memset(name, 0, len);
 
-    sprintf(bankdir, "/%d", b);
+    snprintf_P(bankdir, strlen(bankdir), PSTR("/%d"), b);
 
     // try to open directory
     sysex = SD.open(bankdir);
@@ -1698,7 +1698,7 @@ bool get_voice_name(uint8_t b, uint8_t v, char* name, uint8_t len)
     v = constrain(v, 0, MAX_VOICES - 1);
 
     get_bank_name(b, bank_name, sizeof(bank_name));
-    sprintf(filename, "/%d/%s.syx", b, bank_name);
+    snprintf_P(filename, strlen(filename), PSTR("/%d/%s.syx"), b, bank_name);
 #ifdef DEBUG
     Serial.print(F("Reading voice-name from ["));
     Serial.print(filename);
@@ -1742,7 +1742,7 @@ bool get_voice_by_bank_name(uint8_t b, const char* bank_name, uint8_t v, char* v
   {
     char filename[FILENAME_LEN];
 
-    sprintf(filename, "/%d/%s.syx", b, bank_name);
+    snprintf_P(filename, strlen(filename), PSTR("/%d/%s.syx"), b, bank_name);
 #ifdef DEBUG
     Serial.print(F("Reading voice-name from ["));
     Serial.print(filename);