diff --git a/Firmware/Dcodes.cpp b/Firmware/Dcodes.cpp
index 4a51b4d74..95daaf805 100644
--- a/Firmware/Dcodes.cpp
+++ b/Firmware/Dcodes.cpp
@@ -44,7 +44,7 @@ void print_hex_word(daddr_t val)
     print_hex_byte(val & 0xFF);
 }
 
-int parse_hex(char* hex, uint8_t* data, int count)
+int parse_hex(const char* hex, uint8_t* data, int count)
 {
 	int parsed = 0;
 	while (*hex)
diff --git a/Firmware/Marlin_main.cpp b/Firmware/Marlin_main.cpp
index e2069d204..6c5c0fef3 100644
--- a/Firmware/Marlin_main.cpp
+++ b/Firmware/Marlin_main.cpp
@@ -4248,7 +4248,7 @@ void process_commands()
     */
 
     else if (code_seen_P(PSTR("M0")) || code_seen_P(PSTR("M1 "))) {// M0 and M1 - (Un)conditional stop - Wait for user button press on LCD
-        char *src = strchr_pointer + 2;
+        const char *src = strchr_pointer + 2;
         codenum = 0;
         bool hasP = false, hasS = false;
         if (code_seen('P')) {
@@ -5675,6 +5675,7 @@ eeprom_update_word((uint16_t*)EEPROM_NOZZLE_DIAMETER_uM,0xFFFF);
           {
               // A new print has started from scratch, reset stats
               failstats_reset_print();
+              sdpos_atomic = 0;
 #ifndef LA_NOCOMPAT
               la10c_reset();
 #endif
@@ -5773,7 +5774,7 @@ eeprom_update_word((uint16_t*)EEPROM_NOZZLE_DIAMETER_uM,0xFFFF);
       }
       starpos = (strchr(strchr_pointer + 4,'*'));
 
-      char* namestartpos = (strchr(strchr_pointer + 4,'!'));   //find ! to indicate filename string start.
+      const char* namestartpos = (strchr(strchr_pointer + 4,'!'));   //find ! to indicate filename string start.
       if(namestartpos==NULL)
       {
         namestartpos=strchr_pointer + 4; //default name position, 4 letters after the M
@@ -5802,6 +5803,7 @@ eeprom_update_word((uint16_t*)EEPROM_NOZZLE_DIAMETER_uM,0xFFFF);
             {
                 // A new print has started from scratch, reset stats
                 failstats_reset_print();
+                sdpos_atomic = 0;
 #ifndef LA_NOCOMPAT
                 la10c_reset();
 #endif
diff --git a/Firmware/cardreader.cpp b/Firmware/cardreader.cpp
index 630b0cbd1..0ff8793dc 100644
--- a/Firmware/cardreader.cpp
+++ b/Firmware/cardreader.cpp
@@ -1008,9 +1008,10 @@ void CardReader::flush_presort() {
 void CardReader::printingHasFinished()
 {
     st_synchronize();
+    file.close();
+
     if(file_subcall_ctr>0) //heading up to a parent file that called current as a procedure.
     {
-      file.close();
       file_subcall_ctr--;
       openFileReadFilteredGcode(filenames[file_subcall_ctr],true);
       setIndex(filespos[file_subcall_ctr]);
@@ -1018,8 +1019,6 @@ void CardReader::printingHasFinished()
     }
     else
     {
-      quickStop();
-      file.close();
       sdprinting = false;
       if(SD_FINISHED_STEPPERRELEASE)
       {
diff --git a/Firmware/cmdqueue.cpp b/Firmware/cmdqueue.cpp
index 0380c16d1..e53122a4f 100755
--- a/Firmware/cmdqueue.cpp
+++ b/Firmware/cmdqueue.cpp
@@ -534,7 +534,7 @@ void get_command()
     }
 
   #ifdef SDSUPPORT
-  if(!card.sdprinting || serial_count!=0){
+  if(!card.sdprinting || !card.isFileOpen() || serial_count!=0){
     // If there is a half filled buffer from serial line, wait until return before
     // continuing with the serial line.
      return;
@@ -631,6 +631,10 @@ void get_command()
       // cleared by printingHasFinished after peforming all remaining moves.
       if(!cmdqueue_calc_sd_length())
       {
+          // queue is complete, but before we process EOF commands prevent
+          // re-entry by disabling SD processing from any st_synchronize call
+          card.closefile();
+
           SERIAL_PROTOCOLLNRPGM(_n("Done printing file"));////MSG_FILE_PRINTED
           stoptime=_millis();
           char time[30];
diff --git a/Firmware/util.cpp b/Firmware/util.cpp
index 7b192b8c3..3d789e08f 100644
--- a/Firmware/util.cpp
+++ b/Firmware/util.cpp
@@ -431,7 +431,7 @@ lcd_update_enable(true);           // display / status-line recovery
 #define GCODE_DELIMITER '"'
 #define ELLIPSIS "..."
 
-char* code_string(char* pStr,size_t* nLength)
+char* code_string(const char* pStr,size_t* nLength)
 {
 char* pStrBegin;
 char* pStrEnd;
@@ -444,11 +444,10 @@ pStrEnd=strchr(pStrBegin,GCODE_DELIMITER);
 if(!pStrEnd)
      return(NULL);
 *nLength=pStrEnd-pStrBegin;
-pStrBegin[*nLength] = '\0';
 return pStrBegin;
 }
 
-void printer_smodel_check(char* pStrPos)
+void printer_smodel_check(const char* pStrPos)
 {
 char* pResult;
 size_t nLength,nPrinterNameLength;
@@ -458,7 +457,7 @@ pResult = code_string(pStrPos,&nLength);
 
 if(pResult != NULL && nLength == nPrinterNameLength) {
      // Only compare them if the lengths match
-     if (strcmp_P(pResult, sPrinterName) == 0) return;
+     if (strncmp_P(pResult, sPrinterName, nLength) == 0) return;
 }
 
 switch(oCheckModel)
diff --git a/Firmware/util.h b/Firmware/util.h
index 6d34aa081..7533429e2 100644
--- a/Firmware/util.h
+++ b/Firmware/util.h
@@ -104,7 +104,7 @@ extern ClCheckGcode oCheckGcode;
 void fCheckModeInit();
 void nozzle_diameter_check(uint16_t nDiameter);
 void printer_model_check(uint16_t nPrinterModel);
-void printer_smodel_check(char* pStrPos);
+void printer_smodel_check(const char* pStrPos);
 void fw_version_check(const char *pVersion);
 void gcode_level_check(uint16_t nGcodeLevel);