diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index 19aaedf7c65df..d2a9f395b7068 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -782,7 +782,7 @@ inline void manage_inactivity(const bool no_stepper_sleep=false) {
  *  - Update the Průša MMU2
  *  - Handle Joystick jogging
  */
-void idle(bool no_stepper_sleep/*=false*/) {
+void idle(const bool no_stepper_sleep/*=false*/) {
   #ifdef MAX7219_DEBUG_PROFILE
     CodeProfiler idle_profiler;
   #endif
diff --git a/Marlin/src/MarlinCore.h b/Marlin/src/MarlinCore.h
index f80405a302ee1..e9c63bb31f353 100644
--- a/Marlin/src/MarlinCore.h
+++ b/Marlin/src/MarlinCore.h
@@ -30,7 +30,7 @@
 void stop();
 
 // Pass true to keep steppers from timing out
-void idle(bool no_stepper_sleep=false);
+void idle(const bool no_stepper_sleep=false);
 inline void idle_no_sleep() { idle(true); }
 
 #if ENABLED(G38_PROBE_TARGET)
diff --git a/Marlin/src/lcd/extui/mks_ui/SPIFlashStorage.cpp b/Marlin/src/lcd/extui/mks_ui/SPIFlashStorage.cpp
index 6508f6f02473d..43149dc60c586 100644
--- a/Marlin/src/lcd/extui/mks_ui/SPIFlashStorage.cpp
+++ b/Marlin/src/lcd/extui/mks_ui/SPIFlashStorage.cpp
@@ -148,7 +148,7 @@ uint32_t SPIFlashStorage::m_startAddress;
 
 #endif // HAS_SPI_FLASH_COMPRESSION
 
-void SPIFlashStorage::beginWrite(uint32_t startAddress) {
+void SPIFlashStorage::beginWrite(const uint32_t startAddress) {
   m_pageDataUsed = 0;
   m_currentPage = 0;
   m_startAddress = startAddress;
@@ -171,7 +171,7 @@ void SPIFlashStorage::endWrite() {
   #endif
 }
 
-void SPIFlashStorage::savePage(uint8_t *buffer) {
+void SPIFlashStorage::savePage(uint8_t * const buffer) {
   W25QXX.SPI_FLASH_BufferWrite(buffer, m_startAddress + (SPI_FLASH_PageSize * m_currentPage), SPI_FLASH_PageSize);
   // Test env
   // char fname[256];
@@ -181,7 +181,7 @@ void SPIFlashStorage::savePage(uint8_t *buffer) {
   // fclose(fp);
 }
 
-void SPIFlashStorage::loadPage(uint8_t *buffer) {
+void SPIFlashStorage::loadPage(uint8_t * const buffer) {
   W25QXX.SPI_FLASH_BufferRead(buffer, m_startAddress + (SPI_FLASH_PageSize * m_currentPage), SPI_FLASH_PageSize);
   // Test env
   // char fname[256];
@@ -260,7 +260,7 @@ void SPIFlashStorage::readPage() {
   #endif
 }
 
-uint16_t SPIFlashStorage::inData(uint8_t *data, uint16_t size) {
+uint16_t SPIFlashStorage::inData(const uint8_t * const data, uint16_t size) {
   // Don't write more than we can
   NOMORE(size, pageDataFree());
   memcpy(m_pageData + m_pageDataUsed, data, size);
@@ -268,12 +268,12 @@ uint16_t SPIFlashStorage::inData(uint8_t *data, uint16_t size) {
   return size;
 }
 
-void SPIFlashStorage::writeData(uint8_t *data, uint16_t size) {
+void SPIFlashStorage::writeData(const uint8_t *data, uint16_t size) {
   // Flush a page if needed
   if (pageDataFree() == 0) flushPage();
 
   while (size > 0) {
-    uint16_t written = inData(data, size);
+    const uint16_t written = inData(data, size);
     size -= written;
     // Need to write more? Flush page and continue!
     if (size > 0) {
@@ -283,7 +283,7 @@ void SPIFlashStorage::writeData(uint8_t *data, uint16_t size) {
   }
 }
 
-void SPIFlashStorage::beginRead(uint32_t startAddress) {
+void SPIFlashStorage::beginRead(const uint32_t startAddress) {
   m_startAddress = startAddress;
   m_currentPage = 0;
   // Nothing in memory now
@@ -293,7 +293,7 @@ void SPIFlashStorage::beginRead(uint32_t startAddress) {
   #endif
 }
 
-uint16_t SPIFlashStorage::outData(uint8_t *data, uint16_t size) {
+uint16_t SPIFlashStorage::outData(uint8_t * const data, uint16_t size) {
   // Don't read more than we have
   NOMORE(size, pageDataFree());
   memcpy(data, m_pageData + m_pageDataUsed, size);
@@ -306,7 +306,7 @@ void SPIFlashStorage::readData(uint8_t *data, uint16_t size) {
   if (pageDataFree() == 0) readPage();
 
   while (size > 0) {
-    uint16_t read = outData(data, size);
+    const uint16_t read = outData(data, size);
     size -= read;
     // Need to write more? Flush page and continue!
     if (size > 0) {
diff --git a/Marlin/src/lcd/extui/mks_ui/SPIFlashStorage.h b/Marlin/src/lcd/extui/mks_ui/SPIFlashStorage.h
index 72394286ac58b..bd7109b7acbd4 100644
--- a/Marlin/src/lcd/extui/mks_ui/SPIFlashStorage.h
+++ b/Marlin/src/lcd/extui/mks_ui/SPIFlashStorage.h
@@ -75,23 +75,23 @@
 class SPIFlashStorage {
 public:
   // Write operation
-  static void beginWrite(uint32_t startAddress);
+  static void beginWrite(const uint32_t startAddress);
   static void endWrite();
-  static void writeData(uint8_t *data, uint16_t size);
+  static void writeData(const uint8_t *data, uint16_t size);
 
   // Read operation
-  static void beginRead(uint32_t startAddress);
+  static void beginRead(const uint32_t startAddress);
   static void readData(uint8_t *data, uint16_t size);
 
   static uint32_t getCurrentPage() { return m_currentPage; }
 
 private:
   static void flushPage();
-  static void savePage(uint8_t *buffer);
-  static void loadPage(uint8_t *buffer);
+  static void savePage(uint8_t * const buffer);
+  static void loadPage(uint8_t * const buffer);
   static void readPage();
-  static uint16_t inData(uint8_t *data, uint16_t size);
-  static uint16_t outData(uint8_t *data, uint16_t size);
+  static uint16_t inData(const uint8_t * const data, uint16_t size);
+  static uint16_t outData(uint8_t * const data, uint16_t size);
 
   static uint8_t m_pageData[SPI_FLASH_PageSize];
   static uint32_t m_currentPage;
diff --git a/Marlin/src/sd/Sd2Card.cpp b/Marlin/src/sd/Sd2Card.cpp
index 2d84c95a3d195..81cc03230483a 100644
--- a/Marlin/src/sd/Sd2Card.cpp
+++ b/Marlin/src/sd/Sd2Card.cpp
@@ -345,7 +345,7 @@ bool DiskIODriver_SPI_SD::init(const uint8_t sckRateID, const pin_t chipSelectPi
  * \param[out] dst Pointer to the location that will receive the data.
  * \return true for success, false for failure.
  */
-bool DiskIODriver_SPI_SD::readBlock(uint32_t blockNumber, uint8_t *dst) {
+bool DiskIODriver_SPI_SD::readBlock(uint32_t blockNumber, uint8_t * const dst) {
   #if IS_TEENSY_35_36 || IS_TEENSY_40_41
     return 0 == SDHC_CardReadBlock(dst, blockNumber);
   #endif
@@ -385,7 +385,7 @@ bool DiskIODriver_SPI_SD::readBlock(uint32_t blockNumber, uint8_t *dst) {
  *
  * \return true for success, false for failure.
  */
-bool DiskIODriver_SPI_SD::readData(uint8_t *dst) {
+bool DiskIODriver_SPI_SD::readData(uint8_t * const dst) {
   chipSelect();
   return readData(dst, 512);
 }
@@ -455,7 +455,7 @@ bool DiskIODriver_SPI_SD::readData(uint8_t *dst) {
 
 #endif // SD_CHECK_AND_RETRY
 
-bool DiskIODriver_SPI_SD::readData(uint8_t *dst, const uint16_t count) {
+bool DiskIODriver_SPI_SD::readData(uint8_t * const dst, const uint16_t count) {
   bool success = false;
 
   const millis_t read_timeout = millis() + SD_READ_TIMEOUT;
@@ -487,8 +487,8 @@ bool DiskIODriver_SPI_SD::readData(uint8_t *dst, const uint16_t count) {
 }
 
 /** read CID or CSR register */
-bool DiskIODriver_SPI_SD::readRegister(const uint8_t cmd, void *buf) {
-  uint8_t *dst = reinterpret_cast<uint8_t*>(buf);
+bool DiskIODriver_SPI_SD::readRegister(const uint8_t cmd, void * const buf) {
+  uint8_t * const dst = reinterpret_cast<uint8_t*>(buf);
   if (cardCommand(cmd, 0)) {
     error(SD_CARD_ERROR_READ_REG);
     chipDeselect();
@@ -567,7 +567,7 @@ void DiskIODriver_SPI_SD::error(const uint8_t code) { errorCode_ = code; }
  * \param[in] src Pointer to the location of the data to be written.
  * \return true for success, false for failure.
  */
-bool DiskIODriver_SPI_SD::writeBlock(uint32_t blockNumber, const uint8_t *src) {
+bool DiskIODriver_SPI_SD::writeBlock(uint32_t blockNumber, const uint8_t * const src) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   #if IS_TEENSY_35_36 || IS_TEENSY_40_41
@@ -598,7 +598,7 @@ bool DiskIODriver_SPI_SD::writeBlock(uint32_t blockNumber, const uint8_t *src) {
  * \param[in] src Pointer to the location of the data to be written.
  * \return true for success, false for failure.
  */
-bool DiskIODriver_SPI_SD::writeData(const uint8_t *src) {
+bool DiskIODriver_SPI_SD::writeData(const uint8_t * const src) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   bool success = true;
@@ -613,7 +613,7 @@ bool DiskIODriver_SPI_SD::writeData(const uint8_t *src) {
 }
 
 // Send one block of data for write block or write multiple blocks
-bool DiskIODriver_SPI_SD::writeData(const uint8_t token, const uint8_t *src) {
+bool DiskIODriver_SPI_SD::writeData(const uint8_t token, const uint8_t * const src) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   const uint16_t crc = TERN(SD_CHECK_AND_RETRY, CRC_CCITT(src, 512), 0xFFFF);
diff --git a/Marlin/src/sd/Sd2Card.h b/Marlin/src/sd/Sd2Card.h
index e0dce02a02365..23677b24fa4bd 100644
--- a/Marlin/src/sd/Sd2Card.h
+++ b/Marlin/src/sd/Sd2Card.h
@@ -143,7 +143,7 @@ class DiskIODriver_SPI_SD : public DiskIODriver {
    *
    * \return true for success or false for failure.
    */
-  bool readCID(cid_t *cid) { return readRegister(CMD10, cid); }
+  bool readCID(cid_t * const cid) { return readRegister(CMD10, cid); }
 
   /**
    * Read a card's CSD register. The CSD contains Card-Specific Data that
@@ -153,18 +153,18 @@ class DiskIODriver_SPI_SD : public DiskIODriver {
    *
    * \return true for success or false for failure.
    */
-  inline bool readCSD(csd_t *csd) override { return readRegister(CMD9, csd); }
+  inline bool readCSD(csd_t * const csd) override { return readRegister(CMD9, csd); }
 
-  bool readData(uint8_t *dst) override;
+  bool readData(uint8_t * const dst) override;
   bool readStart(uint32_t blockNumber) override;
   bool readStop() override;
 
-  bool writeData(const uint8_t *src) override;
-  bool writeStart(const uint32_t blockNumber, const uint32_t eraseCount) override;
+  bool writeData(const uint8_t * const src) override;
+  bool writeStart(uint32_t blockNumber, const uint32_t eraseCount) override;
   bool writeStop() override;
 
-  bool readBlock(uint32_t block, uint8_t *dst) override;
-  bool writeBlock(uint32_t blockNumber, const uint8_t *src) override;
+  bool readBlock(uint32_t blockNumber, uint8_t * const dst) override;
+  bool writeBlock(uint32_t blockNumber, const uint8_t * const src) override;
 
   uint32_t cardSize() override;
 
@@ -187,11 +187,11 @@ class DiskIODriver_SPI_SD : public DiskIODriver {
   }
   uint8_t cardCommand(const uint8_t cmd, const uint32_t arg);
 
-  bool readData(uint8_t *dst, const uint16_t count);
-  bool readRegister(const uint8_t cmd, void *buf);
+  bool readData(uint8_t * const dst, const uint16_t count);
+  bool readRegister(const uint8_t cmd, void * const buf);
   void chipDeselect();
   void chipSelect();
   inline void type(const uint8_t value) { type_ = value; }
   bool waitNotBusy(const millis_t timeout_ms);
-  bool writeData(const uint8_t token, const uint8_t *src);
+  bool writeData(const uint8_t token, const uint8_t * const src);
 };
diff --git a/Marlin/src/sd/SdBaseFile.cpp b/Marlin/src/sd/SdBaseFile.cpp
index 818f0dcb37373..4f4a8e9fa992e 100644
--- a/Marlin/src/sd/SdBaseFile.cpp
+++ b/Marlin/src/sd/SdBaseFile.cpp
@@ -91,7 +91,7 @@ bool SdBaseFile::addDirCluster() {
 // cache a file's directory entry
 // cache the current "dirBlock_" and return the entry at index "dirIndex_"
 // return pointer to cached entry or null for failure
-dir_t* SdBaseFile::cacheDirEntry(uint8_t action) {
+dir_t* SdBaseFile::cacheDirEntry(const uint8_t action) {
   if (!vol_->cacheRawBlock(dirBlock_, action)) return nullptr;
   return vol_->cache()->dir + dirIndex_;
 }
@@ -119,7 +119,7 @@ bool SdBaseFile::close() {
  * Reasons for failure include file is not contiguous, file has zero length
  * or an I/O error occurred.
  */
-bool SdBaseFile::contiguousRange(uint32_t *bgnBlock, uint32_t *endBlock) {
+bool SdBaseFile::contiguousRange(uint32_t * const bgnBlock, uint32_t * const endBlock) {
   // error if no blocks
   if (firstCluster_ == 0) return false;
 
@@ -156,7 +156,7 @@ bool SdBaseFile::contiguousRange(uint32_t *bgnBlock, uint32_t *endBlock) {
  * a file is already open, the file already exists, the root
  * directory is full or an I/O error.
  */
-bool SdBaseFile::createContiguous(SdBaseFile *dirFile, const char *path, uint32_t size) {
+bool SdBaseFile::createContiguous(SdBaseFile * const dirFile, const char * const path, const uint32_t size) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   uint32_t count;
@@ -301,7 +301,7 @@ bool SdBaseFile::getDosName(char * const name) {
   return true;
 }
 
-void SdBaseFile::getpos(filepos_t *pos) {
+void SdBaseFile::getpos(filepos_t * const pos) {
   pos->position = curPosition_;
   pos->cluster = curCluster_;
 }
@@ -337,7 +337,7 @@ void SdBaseFile::ls(uint8_t flags, uint8_t indent) {
 
 // saves 32 bytes on stack for ls recursion
 // return 0 - EOF, 1 - normal file, or 2 - directory
-int8_t SdBaseFile::lsPrintNext(uint8_t flags, uint8_t indent) {
+int8_t SdBaseFile::lsPrintNext(const uint8_t flags, const uint8_t indent) {
   dir_t dir;
   uint8_t w = 0;
 
@@ -400,7 +400,7 @@ uint8_t lfn_checksum(const uint8_t *name) {
 }
 
 // Format directory name field from a 8.3 name string
-bool SdBaseFile::make83Name(const char *str, uint8_t *name, const char **ptr) {
+bool SdBaseFile::make83Name(const char *str, uint8_t * const name, const char **ptr) {
   uint8_t n = 7,                      // Max index until a dot is found
           i = 11;
   while (i) name[--i] = ' ';          // Set whole FILENAME.EXT to spaces
@@ -437,13 +437,11 @@ bool SdBaseFile::make83Name(const char *str, uint8_t *name, const char **ptr) {
  * Reasons for failure include this file is already open, \a parent is not a
  * directory, \a path is invalid or already exists in \a parent.
  */
-bool SdBaseFile::mkdir(SdBaseFile *parent, const char *path, bool pFlag) {
+bool SdBaseFile::mkdir(SdBaseFile *parent, const char *path, const bool pFlag/*=true*/) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
-  uint8_t dname[11];
-  SdBaseFile dir1, dir2;
-  SdBaseFile *sub = &dir1;
-  SdBaseFile *start = parent;
+  SdBaseFile dir1, dir2, *sub = &dir1;
+  SdBaseFile * const start = parent;
 
   #if ENABLED(LONG_FILENAME_WRITE_SUPPORT)
     uint8_t dlname[LONG_FILENAME_LENGTH];
@@ -459,6 +457,7 @@ bool SdBaseFile::mkdir(SdBaseFile *parent, const char *path, bool pFlag) {
     }
   }
 
+  uint8_t dname[11];
   for (;;) {
     if (!TERN(LONG_FILENAME_WRITE_SUPPORT, parsePath(path, dname, dlname, &path), make83Name(path, dname, &path))) return false;
     while (*path == '/') path++;
@@ -474,7 +473,7 @@ bool SdBaseFile::mkdir(SdBaseFile *parent, const char *path, bool pFlag) {
   return mkdir(parent, dname OPTARG(LONG_FILENAME_WRITE_SUPPORT, dlname));
 }
 
-bool SdBaseFile::mkdir(SdBaseFile *parent, const uint8_t dname[11]
+bool SdBaseFile::mkdir(SdBaseFile * const parent, const uint8_t dname[11]
   OPTARG(LONG_FILENAME_WRITE_SUPPORT, const uint8_t dlname[LONG_FILENAME_LENGTH])
 ) {
   if (ENABLED(SDCARD_READONLY)) return false;
@@ -541,7 +540,7 @@ bool SdBaseFile::mkdir(SdBaseFile *parent, const uint8_t dname[11]
  *
  * \return true for success, false for failure.
  */
-bool SdBaseFile::open(const char *path, uint8_t oflag) {
+bool SdBaseFile::open(const char * const path, const uint8_t oflag) {
   return open(cwd_, path, oflag);
 }
 
@@ -595,7 +594,7 @@ bool SdBaseFile::open(const char *path, uint8_t oflag) {
  * a directory, \a path is invalid, the file does not exist
  * or can't be opened in the access mode specified by oflag.
  */
-bool SdBaseFile::open(SdBaseFile *dirFile, const char *path, uint8_t oflag) {
+bool SdBaseFile::open(SdBaseFile * const dirFile, const char *path, const uint8_t oflag) {
   uint8_t dname[11];
   SdBaseFile dir1, dir2;
   SdBaseFile *parent = dirFile, *sub = &dir1;
@@ -627,9 +626,9 @@ bool SdBaseFile::open(SdBaseFile *dirFile, const char *path, uint8_t oflag) {
 }
 
 // open with filename in dname and long filename in dlname
-bool SdBaseFile::open(SdBaseFile *dirFile, const uint8_t dname[11]
+bool SdBaseFile::open(SdBaseFile * const dirFile, const uint8_t dname[11]
     OPTARG(LONG_FILENAME_WRITE_SUPPORT, const uint8_t dlname[LONG_FILENAME_LENGTH])
-  , uint8_t oflag
+  , const uint8_t oflag
 ) {
   bool emptyFound = false, fileFound = false;
   uint8_t index = 0;
@@ -876,7 +875,7 @@ bool SdBaseFile::open(SdBaseFile *dirFile, const uint8_t dname[11]
  * See open() by path for definition of flags.
  * \return true for success or false for failure.
  */
-bool SdBaseFile::open(SdBaseFile *dirFile, uint16_t index, uint8_t oflag) {
+bool SdBaseFile::open(SdBaseFile *dirFile, uint16_t index, const uint8_t oflag) {
   vol_ = dirFile->vol_;
 
   // error if already open
@@ -902,7 +901,7 @@ bool SdBaseFile::open(SdBaseFile *dirFile, uint16_t index, uint8_t oflag) {
 }
 
 // open a cached directory entry. Assumes vol_ is initialized
-bool SdBaseFile::openCachedEntry(uint8_t dirIndex, uint8_t oflag) {
+bool SdBaseFile::openCachedEntry(const uint8_t dirIndex, const uint8_t oflag) {
   dir_t *p;
 
   #if ENABLED(SDCARD_READONLY)
@@ -962,7 +961,7 @@ bool SdBaseFile::openCachedEntry(uint8_t dirIndex, uint8_t oflag) {
  * See open() by path for definition of flags.
  * \return true for success or false for failure.
  */
-bool SdBaseFile::openNext(SdBaseFile *dirFile, uint8_t oflag) {
+bool SdBaseFile::openNext(SdBaseFile *dirFile, const uint8_t oflag) {
   if (!dirFile) return false;
 
   // error if already open
@@ -1017,7 +1016,7 @@ bool SdBaseFile::openNext(SdBaseFile *dirFile, uint8_t oflag) {
    * \return true if the dirname is a long file name (LFN)
    * \return false if the dirname is a short file name 8.3 (SFN)
    */
-  bool SdBaseFile::isDirNameLFN(const char *dirname) {
+  bool SdBaseFile::isDirNameLFN(const char * const dirname) {
     uint8_t length = strlen(dirname), idx = length;
     bool dotFound = false;
     if (idx > 12) return true;            // LFN due to filename length > 12 ("filename.ext")
@@ -1048,7 +1047,7 @@ bool SdBaseFile::openNext(SdBaseFile *dirFile, uint8_t oflag) {
    * The SFN is without dot ("FILENAMEEXT")
    * The LFN is complete ("Filename.ext")
    */
-  bool SdBaseFile::parsePath(const char *path, uint8_t *name, uint8_t *lname, const char **ptrNextPath) {
+  bool SdBaseFile::parsePath(const char *path, uint8_t * const name, uint8_t * const lname, const char **ptrNextPath) {
     // Init randomizer for SFN generation
     randomSeed(millis());
     // Parse the LFN
@@ -1136,7 +1135,7 @@ bool SdBaseFile::openNext(SdBaseFile *dirFile, uint8_t oflag) {
   /**
    * Get the LFN filename block from a dir. Get the block in lname at startOffset
    */
-  void SdBaseFile::getLFNName(vfat_t *pFatDir, char *lname, uint8_t sequenceNumber) {
+  void SdBaseFile::getLFNName(vfat_t *pFatDir, char *lname, const uint8_t sequenceNumber) {
     const uint8_t startOffset = (sequenceNumber - 1) * FILENAME_LENGTH;
     LOOP_L_N(i, FILENAME_LENGTH) {
       const uint16_t utf16_ch = (i >= 11) ? pFatDir->name3[i - 11] : (i >= 5) ? pFatDir->name2[i - 5] : pFatDir->name1[i];
@@ -1156,7 +1155,7 @@ bool SdBaseFile::openNext(SdBaseFile *dirFile, uint8_t oflag) {
   /**
    * Set the LFN filename block lname to a dir. Put the block based on sequence number
    */
-  void SdBaseFile::setLFNName(vfat_t *pFatDir, char *lname, uint8_t sequenceNumber) {
+  void SdBaseFile::setLFNName(vfat_t *pFatDir, char *lname, const uint8_t sequenceNumber) {
     const uint8_t startOffset = (sequenceNumber - 1) * FILENAME_LENGTH,
                   nameLength = strlen(lname);
     LOOP_L_N(i, FILENAME_LENGTH) {
@@ -1305,7 +1304,7 @@ static void print2u(const uint8_t v) {
  * \param[in] pr Print stream for output.
  * \param[in] fatDate The date field from a directory entry.
  */
-void SdBaseFile::printFatDate(uint16_t fatDate) {
+void SdBaseFile::printFatDate(const uint16_t fatDate) {
   SERIAL_ECHO(FAT_YEAR(fatDate));
   SERIAL_CHAR('-');
   print2u(FAT_MONTH(fatDate));
@@ -1322,7 +1321,7 @@ void SdBaseFile::printFatDate(uint16_t fatDate) {
  * \param[in] pr Print stream for output.
  * \param[in] fatTime The time field from a directory entry.
  */
-void SdBaseFile::printFatTime(uint16_t fatTime) {
+void SdBaseFile::printFatTime(const uint16_t fatTime) {
   print2u(FAT_HOUR(fatTime));
   SERIAL_CHAR(':');
   print2u(FAT_MINUTE(fatTime));
@@ -1367,7 +1366,7 @@ int16_t SdBaseFile::read() {
  * read() called before a file has been opened, corrupt file system
  * or an I/O error occurred.
  */
-int16_t SdBaseFile::read(void *buf, uint16_t nbyte) {
+int16_t SdBaseFile::read(void * const buf, uint16_t nbyte) {
   uint8_t *dst = reinterpret_cast<uint8_t*>(buf);
   uint16_t offset, toRead;
   uint32_t block;  // raw device block number
@@ -1429,7 +1428,7 @@ int16_t SdBaseFile::read(void *buf, uint16_t nbyte) {
  * readDir() called before a directory has been opened, this is not
  * a directory file or an I/O error occurred.
  */
-int8_t SdBaseFile::readDir(dir_t *dir, char * const longFilename) {
+int8_t SdBaseFile::readDir(dir_t * const dir, char * const longFilename) {
   int16_t n;
   // if not a directory file or miss-positioned return an error
   if (!isDir() || (0x1F & curPosition_)) return -1;
@@ -1676,7 +1675,7 @@ bool SdBaseFile::remove() {
  * \a dirFile is not a directory, \a path is not found
  * or an I/O error occurred.
  */
-bool SdBaseFile::remove(SdBaseFile *dirFile, const char *path) {
+bool SdBaseFile::remove(SdBaseFile * const dirFile, const char * const path) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   SdBaseFile file;
@@ -1715,7 +1714,7 @@ bool SdBaseFile::hide(const bool hidden) {
  * Reasons for failure include \a dirFile is not open or is not a directory
  * file, newPath is invalid or already exists, or an I/O error occurs.
  */
-bool SdBaseFile::rename(SdBaseFile *dirFile, const char *newPath) {
+bool SdBaseFile::rename(SdBaseFile * const dirFile, const char * const newPath) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   uint32_t dirCluster = 0;
@@ -1900,7 +1899,7 @@ bool SdBaseFile::rmRfStar() {
  * \param[in] oflag Values for \a oflag are constructed by a bitwise-inclusive
  * OR of open flags. see SdBaseFile::open(SdBaseFile*, const char*, uint8_t).
  */
-SdBaseFile::SdBaseFile(const char *path, uint8_t oflag) {
+SdBaseFile::SdBaseFile(const char * const path, const uint8_t oflag) {
   type_ = FAT_FILE_TYPE_CLOSED;
   writeError = false;
   open(path, oflag);
@@ -1943,7 +1942,7 @@ bool SdBaseFile::seekSet(const uint32_t pos) {
   return true;
 }
 
-void SdBaseFile::setpos(filepos_t *pos) {
+void SdBaseFile::setpos(filepos_t * const pos) {
   curPosition_ = pos->position;
   curCluster_ = pos->cluster;
 }
@@ -1998,7 +1997,7 @@ bool SdBaseFile::sync() {
  *
  * \return true for success, false for failure.
  */
-bool SdBaseFile::timestamp(SdBaseFile *file) {
+bool SdBaseFile::timestamp(SdBaseFile * const file) {
   dir_t dir;
 
   // get timestamps
@@ -2055,8 +2054,8 @@ bool SdBaseFile::timestamp(SdBaseFile *file) {
  *
  * \return true for success, false for failure.
  */
-bool SdBaseFile::timestamp(uint8_t flags, uint16_t year, uint8_t month,
-                           uint8_t day, uint8_t hour, uint8_t minute, uint8_t second) {
+bool SdBaseFile::timestamp(const uint8_t flags, const uint16_t year, const uint8_t month,
+                           const uint8_t day, const uint8_t hour, const uint8_t minute, const uint8_t second) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   uint16_t dirDate, dirTime;
diff --git a/Marlin/src/sd/SdBaseFile.h b/Marlin/src/sd/SdBaseFile.h
index 19225170f9ce4..046c2447cb7a6 100644
--- a/Marlin/src/sd/SdBaseFile.h
+++ b/Marlin/src/sd/SdBaseFile.h
@@ -89,7 +89,7 @@ uint8_t const FAT_FILE_TYPE_CLOSED = 0,                           // This file h
  *
  * \return Packed date for dir_t entry.
  */
-static inline uint16_t FAT_DATE(uint16_t year, uint8_t month, uint8_t day) { return (year - 1980) << 9 | month << 5 | day; }
+static inline uint16_t FAT_DATE(const uint16_t year, const uint8_t month, const uint8_t day) { return (year - 1980) << 9 | month << 5 | day; }
 
 /**
  * year part of FAT directory date field
@@ -97,7 +97,7 @@ static inline uint16_t FAT_DATE(uint16_t year, uint8_t month, uint8_t day) { ret
  *
  * \return Extracted year [1980,2107]
  */
-static inline uint16_t FAT_YEAR(uint16_t fatDate) { return 1980 + (fatDate >> 9); }
+static inline uint16_t FAT_YEAR(const uint16_t fatDate) { return 1980 + (fatDate >> 9); }
 
 /**
  * month part of FAT directory date field
@@ -105,7 +105,7 @@ static inline uint16_t FAT_YEAR(uint16_t fatDate) { return 1980 + (fatDate >> 9)
  *
  * \return Extracted month [1,12]
  */
-static inline uint8_t FAT_MONTH(uint16_t fatDate) { return (fatDate >> 5) & 0xF; }
+static inline uint8_t FAT_MONTH(const uint16_t fatDate) { return (fatDate >> 5) & 0xF; }
 
 /**
  * day part of FAT directory date field
@@ -113,7 +113,7 @@ static inline uint8_t FAT_MONTH(uint16_t fatDate) { return (fatDate >> 5) & 0xF;
  *
  * \return Extracted day [1,31]
  */
-static inline uint8_t FAT_DAY(uint16_t fatDate) { return fatDate & 0x1F; }
+static inline uint8_t FAT_DAY(const uint16_t fatDate) { return fatDate & 0x1F; }
 
 /**
  * time field for FAT directory entry
@@ -123,7 +123,7 @@ static inline uint8_t FAT_DAY(uint16_t fatDate) { return fatDate & 0x1F; }
  *
  * \return Packed time for dir_t entry.
  */
-static inline uint16_t FAT_TIME(uint8_t hour, uint8_t minute, uint8_t second) { return hour << 11 | minute << 5 | second >> 1; }
+static inline uint16_t FAT_TIME(const uint8_t hour, const uint8_t minute, const uint8_t second) { return hour << 11 | minute << 5 | second >> 1; }
 
 /**
  * hour part of FAT directory time field
@@ -131,7 +131,7 @@ static inline uint16_t FAT_TIME(uint8_t hour, uint8_t minute, uint8_t second) {
  *
  * \return Extracted hour [0,23]
  */
-static inline uint8_t FAT_HOUR(uint16_t fatTime) { return fatTime >> 11; }
+static inline uint8_t FAT_HOUR(const uint16_t fatTime) { return fatTime >> 11; }
 
 /**
  * minute part of FAT directory time field
@@ -139,7 +139,7 @@ static inline uint8_t FAT_HOUR(uint16_t fatTime) { return fatTime >> 11; }
  *
  * \return Extracted minute [0,59]
  */
-static inline uint8_t FAT_MINUTE(uint16_t fatTime) { return (fatTime >> 5) & 0x3F; }
+static inline uint8_t FAT_MINUTE(const uint16_t fatTime) { return (fatTime >> 5) & 0x3F; }
 
 /**
  * second part of FAT directory time field
@@ -149,7 +149,7 @@ static inline uint8_t FAT_MINUTE(uint16_t fatTime) { return (fatTime >> 5) & 0x3
  *
  * \return Extracted second [0,58]
  */
-static inline uint8_t FAT_SECOND(uint16_t fatTime) { return 2 * (fatTime & 0x1F); }
+static inline uint8_t FAT_SECOND(const uint16_t fatTime) { return 2 * (fatTime & 0x1F); }
 
 // Default date for file timestamps is 1 Jan 2000
 uint16_t const FAT_DEFAULT_DATE = ((2000 - 1980) << 9) | (1 << 5) | 1;
@@ -163,7 +163,7 @@ uint16_t const FAT_DEFAULT_TIME = (1 << 11);
 class SdBaseFile {
  public:
   SdBaseFile() : writeError(false), type_(FAT_FILE_TYPE_CLOSED) {}
-  SdBaseFile(const char *path, uint8_t oflag);
+  SdBaseFile(const char * const path, const uint8_t oflag);
   ~SdBaseFile() { if (isOpen()) close(); }
 
   /**
@@ -179,18 +179,17 @@ class SdBaseFile {
    * get position for streams
    * \param[out] pos struct to receive position
    */
-  void getpos(filepos_t *pos);
+  void getpos(filepos_t * const pos);
 
   /**
    * set position for streams
    * \param[out] pos struct with value for new position
    */
-  void setpos(filepos_t *pos);
+  void setpos(filepos_t * const pos);
 
   bool close();
-  bool contiguousRange(uint32_t *bgnBlock, uint32_t *endBlock);
-  bool createContiguous(SdBaseFile *dirFile,
-                        const char *path, uint32_t size);
+  bool contiguousRange(uint32_t * const bgnBlock, uint32_t * const endBlock);
+  bool createContiguous(SdBaseFile * const dirFile, const char * const path, const uint32_t size);
   /**
    * \return The current cluster number for a file or directory.
    */
@@ -235,7 +234,7 @@ class SdBaseFile {
    * See the timestamp() function.
    */
   static void dateTimeCallback(
-    void (*dateTime)(uint16_t *date, uint16_t *time)) {
+    void (*dateTime)(uint16_t * const date, uint16_t * const time)) {
     dateTime_ = dateTime;
   }
 
@@ -246,7 +245,7 @@ class SdBaseFile {
   bool dirEntry(dir_t *dir);
   static void dirName(const dir_t& dir, char *name);
   bool exists(const char *name);
-  int16_t fgets(char *str, int16_t num, char *delim = 0);
+  int16_t fgets(char *str, int16_t num, char *delim=0);
 
   /**
    * \return The total number of bytes in a file or directory.
@@ -284,29 +283,29 @@ class SdBaseFile {
   bool isRoot() const { return type_ == FAT_FILE_TYPE_ROOT_FIXED || type_ == FAT_FILE_TYPE_ROOT32; }
 
   bool getDosName(char * const name);
-  void ls(uint8_t flags = 0, uint8_t indent = 0);
-
-  bool mkdir(SdBaseFile *dir, const char *path, bool pFlag = true);
-  bool open(SdBaseFile *dirFile, uint16_t index, uint8_t oflag);
-  bool open(SdBaseFile *dirFile, const char *path, uint8_t oflag);
-  bool open(const char *path, uint8_t oflag = O_READ);
-  bool openNext(SdBaseFile *dirFile, uint8_t oflag);
-  bool openRoot(SdVolume *vol);
+  void ls(uint8_t flags=0, uint8_t indent=0);
+
+  bool mkdir(SdBaseFile *parent, const char *path, const bool pFlag=true);
+  bool open(SdBaseFile * const dirFile, uint16_t index, const uint8_t oflag);
+  bool open(SdBaseFile * const dirFile, const char *path, const uint8_t oflag);
+  bool open(const char * const path, const uint8_t oflag=O_READ);
+  bool openNext(SdBaseFile * const dirFile, const uint8_t oflag);
+  bool openRoot(SdVolume * const vol);
   int peek();
-  static void printFatDate(uint16_t fatDate);
-  static void printFatTime(uint16_t fatTime);
+  static void printFatDate(const uint16_t fatDate);
+  static void printFatTime(const uint16_t fatTime);
   bool printName();
   int16_t read();
-  int16_t read(void *buf, uint16_t nbyte);
-  int8_t readDir(dir_t *dir, char * const longFilename);
-  static bool remove(SdBaseFile *dirFile, const char *path);
+  int16_t read(void * const buf, uint16_t nbyte);
+  int8_t readDir(dir_t * const dir, char * const longFilename);
+  static bool remove(SdBaseFile * const dirFile, const char * const path);
   bool remove();
 
   /**
    * Set the file's current position to zero.
    */
   void rewind() { seekSet(0); }
-  bool rename(SdBaseFile *dirFile, const char *newPath);
+  bool rename(SdBaseFile * const dirFile, const char * const newPath);
   bool rmdir();
   bool rmRfStar();
 
@@ -327,12 +326,12 @@ class SdBaseFile {
    * \param[in] offset The new position in bytes from end-of-file.
    * \return true for success or false for failure.
    */
-  bool seekEnd(const int32_t offset = 0) { return seekSet(fileSize_ + offset); }
+  bool seekEnd(const int32_t offset=0) { return seekSet(fileSize_ + offset); }
   bool seekSet(const uint32_t pos);
   bool sync();
-  bool timestamp(SdBaseFile *file);
-  bool timestamp(uint8_t flag, uint16_t year, uint8_t month, uint8_t day,
-                 uint8_t hour, uint8_t minute, uint8_t second);
+  bool timestamp(SdBaseFile * const file);
+  bool timestamp(const uint8_t flag, const uint16_t year, const uint8_t month, const uint8_t day,
+                 const uint8_t hour, const uint8_t minute, const uint8_t second);
 
   /**
    * Type of file. Use isFile() or isDir() instead of type() if possible.
@@ -379,17 +378,17 @@ class SdBaseFile {
   // private functions
   bool addCluster();
   bool addDirCluster();
-  dir_t* cacheDirEntry(uint8_t action);
-  int8_t lsPrintNext(uint8_t flags, uint8_t indent);
-  static bool make83Name(const char *str, uint8_t *name, const char **ptr);
-  bool mkdir(SdBaseFile *parent, const uint8_t dname[11]
+  dir_t* cacheDirEntry(const uint8_t action);
+  int8_t lsPrintNext(const uint8_t flags, const uint8_t indent);
+  static bool make83Name(const char *str, uint8_t * const name, const char **ptr);
+  bool mkdir(SdBaseFile * const parent, const uint8_t dname[11]
     OPTARG(LONG_FILENAME_WRITE_SUPPORT, const uint8_t dlname[LONG_FILENAME_LENGTH])
   );
   bool open(SdBaseFile *dirFile, const uint8_t dname[11]
       OPTARG(LONG_FILENAME_WRITE_SUPPORT, const uint8_t dlname[LONG_FILENAME_LENGTH])
-    , uint8_t oflag
+    , const uint8_t oflag
   );
-  bool openCachedEntry(uint8_t cacheIndex, uint8_t oflags);
+  bool openCachedEntry(const uint8_t dirIndex, const uint8_t oflags);
   dir_t* readDirCache();
 
   #if ENABLED(UTF_FILENAME_SUPPORT)
@@ -399,11 +398,11 @@ class SdBaseFile {
   // Long Filename create/write support
   #if ENABLED(LONG_FILENAME_WRITE_SUPPORT)
     static bool isDirLFN(const dir_t* dir);
-    static bool isDirNameLFN(const char *dirname);
-    static bool parsePath(const char *str, uint8_t *name, uint8_t *lname, const char **ptr);
+    static bool isDirNameLFN(const char * const dirname);
+    static bool parsePath(const char *str, uint8_t * const name, uint8_t * const lname, const char **ptr);
     // Return the number of entries needed in the FAT for this LFN
-    static inline uint8_t getLFNEntriesNum(const char *lname) { return (strlen(lname) + 12) / 13; }
-    static void getLFNName(vfat_t *vFatDir, char *lname, uint8_t startOffset);
-    static void setLFNName(vfat_t *vFatDir, char *lname, uint8_t lfnSequenceNumber);
+    static uint8_t getLFNEntriesNum(const char * const lname) { return (strlen(lname) + 12) / 13; }
+    static void getLFNName(vfat_t *vFatDir, char *lname, const uint8_t sequenceNumber);
+    static void setLFNName(vfat_t *vFatDir, char *lname, const uint8_t sequenceNumber);
   #endif
 };
diff --git a/Marlin/src/sd/SdFile.cpp b/Marlin/src/sd/SdFile.cpp
index bce96ef02db5e..ac5f6f923414d 100644
--- a/Marlin/src/sd/SdFile.cpp
+++ b/Marlin/src/sd/SdFile.cpp
@@ -43,7 +43,7 @@
  * \param[in] oflag Values for \a oflag are constructed by a bitwise-inclusive
  * OR of open flags. see SdBaseFile::open(SdBaseFile*, const char*, uint8_t).
  */
-SdFile::SdFile(const char *path, uint8_t oflag) : SdBaseFile(path, oflag) { }
+SdFile::SdFile(const char * const path, const uint8_t oflag) : SdBaseFile(path, oflag) { }
 
 /**
  * Write data to an open file.
@@ -60,7 +60,7 @@ SdFile::SdFile(const char *path, uint8_t oflag) : SdBaseFile(path, oflag) { }
  * include write() is called before a file has been opened, write is called
  * for a read-only file, device is full, a corrupt file system or an I/O error.
  */
-int16_t SdFile::write(const void *buf, uint16_t nbyte) { return SdBaseFile::write(buf, nbyte); }
+int16_t SdFile::write(const void * const buf, const uint16_t nbyte) { return SdBaseFile::write(buf, nbyte); }
 
 /**
  * Write a byte to a file. Required by the Arduino Print class.
@@ -68,9 +68,9 @@ int16_t SdFile::write(const void *buf, uint16_t nbyte) { return SdBaseFile::writ
  * Use writeError to check for errors.
  */
 #if ARDUINO >= 100
-  size_t SdFile::write(uint8_t b) { return SdBaseFile::write(&b, 1); }
+  size_t SdFile::write(const uint8_t b) { return SdBaseFile::write(&b, 1); }
 #else
-  void SdFile::write(uint8_t b) { SdBaseFile::write(&b, 1); }
+  void SdFile::write(const uint8_t b) { SdBaseFile::write(&b, 1); }
 #endif
 
 /**
@@ -78,7 +78,7 @@ int16_t SdFile::write(const void *buf, uint16_t nbyte) { return SdBaseFile::writ
  * \param[in] str Pointer to the string.
  * Use writeError to check for errors.
  */
-void SdFile::write(const char *str) { SdBaseFile::write(str, strlen(str)); }
+void SdFile::write(const char * const str) { SdBaseFile::write(str, strlen(str)); }
 
 /**
  * Write a PROGMEM string to a file.
@@ -94,7 +94,7 @@ void SdFile::write_P(PGM_P str) {
  * \param[in] str Pointer to the PROGMEM string.
  * Use writeError to check for errors.
  */
-void SdFile::writeln_P(PGM_P str) {
+void SdFile::writeln_P(PGM_P const str) {
   write_P(str);
   write_P(PSTR("\r\n"));
 }
diff --git a/Marlin/src/sd/SdFile.h b/Marlin/src/sd/SdFile.h
index 81eeadf5b5719..b075239ebba79 100644
--- a/Marlin/src/sd/SdFile.h
+++ b/Marlin/src/sd/SdFile.h
@@ -41,17 +41,17 @@
 class SdFile : public SdBaseFile {
  public:
   SdFile() {}
-  SdFile(const char *name, uint8_t oflag);
+  SdFile(const char * const name, const uint8_t oflag);
   #if ARDUINO >= 100
-    size_t write(uint8_t b);
+    size_t write(const uint8_t b);
   #else
-    void write(uint8_t b);
+    void write(const uint8_t b);
   #endif
 
-  int16_t write(const void *buf, uint16_t nbyte);
-  void write(const char *str);
+  int16_t write(const void * const buf, const uint16_t nbyte);
+  void write(const char * const str);
   void write_P(PGM_P str);
-  void writeln_P(PGM_P str);
+  void writeln_P(PGM_P const str);
 };
 
 using MediaFile = SdFile;
diff --git a/Marlin/src/sd/SdVolume.cpp b/Marlin/src/sd/SdVolume.cpp
index 1b1fdc5a7c1e2..8c06c745371ba 100644
--- a/Marlin/src/sd/SdVolume.cpp
+++ b/Marlin/src/sd/SdVolume.cpp
@@ -47,7 +47,7 @@
 #endif
 
 // find a contiguous group of clusters
-bool SdVolume::allocContiguous(uint32_t count, uint32_t *curCluster) {
+bool SdVolume::allocContiguous(const uint32_t count, uint32_t * const curCluster) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   // start of group
@@ -138,7 +138,7 @@ bool SdVolume::cacheFlush() {
   return true;
 }
 
-bool SdVolume::cacheRawBlock(uint32_t blockNumber, bool dirty) {
+bool SdVolume::cacheRawBlock(const uint32_t blockNumber, const bool dirty) {
   if (cacheBlockNumber_ != blockNumber) {
     if (!cacheFlush()) return false;
     if (!sdCard_->readBlock(blockNumber, cacheBuffer_.data)) return false;
@@ -149,7 +149,7 @@ bool SdVolume::cacheRawBlock(uint32_t blockNumber, bool dirty) {
 }
 
 // return the size in bytes of a cluster chain
-bool SdVolume::chainSize(uint32_t cluster, uint32_t *size) {
+bool SdVolume::chainSize(uint32_t cluster, uint32_t * const size) {
   uint32_t s = 0;
   do {
     if (!fatGet(cluster, &cluster)) return false;
@@ -160,7 +160,7 @@ bool SdVolume::chainSize(uint32_t cluster, uint32_t *size) {
 }
 
 // Fetch a FAT entry
-bool SdVolume::fatGet(uint32_t cluster, uint32_t *value) {
+bool SdVolume::fatGet(const uint32_t cluster, uint32_t * const value) {
   uint32_t lba;
   if (cluster > (clusterCount_ + 1)) return false;
   if (FAT12_SUPPORT && fatType_ == 12) {
@@ -195,7 +195,7 @@ bool SdVolume::fatGet(uint32_t cluster, uint32_t *value) {
 }
 
 // Store a FAT entry
-bool SdVolume::fatPut(uint32_t cluster, uint32_t value) {
+bool SdVolume::fatPut(const uint32_t cluster, const uint32_t value) {
   if (ENABLED(SDCARD_READONLY)) return false;
 
   uint32_t lba;
@@ -326,7 +326,7 @@ int32_t SdVolume::freeClusterCount() {
  * Reasons for failure include not finding a valid partition, not finding a valid
  * FAT file system in the specified partition or an I/O error.
  */
-bool SdVolume::init(DiskIODriver* dev, uint8_t part) {
+bool SdVolume::init(DiskIODriver * const dev, const uint8_t part) {
   uint32_t totalBlocks, volumeStartBlock = 0;
   fat32_boot_t *fbs;
 
diff --git a/Marlin/src/sd/SdVolume.h b/Marlin/src/sd/SdVolume.h
index 3097773030927..ccf595a593d68 100644
--- a/Marlin/src/sd/SdVolume.h
+++ b/Marlin/src/sd/SdVolume.h
@@ -93,8 +93,8 @@ class SdVolume {
    * Reasons for failure include not finding a valid partition, not finding
    * a valid FAT file system or an I/O error.
    */
-  bool init(DiskIODriver *dev) { return init(dev, 1) || init(dev, 0); }
-  bool init(DiskIODriver *dev, uint8_t part);
+  bool init(DiskIODriver * const dev) { return init(dev, 1) || init(dev, 0); }
+  bool init(DiskIODriver * const dev, const uint8_t part);
 
   // inline functions that return volume info
   uint8_t blocksPerCluster() const { return blocksPerCluster_; } //> \return The volume's cluster size in blocks.
@@ -127,7 +127,7 @@ class SdVolume {
    * \param[out] v value of entry
    * \return true for success or false for failure
    */
-  bool dbgFat(uint32_t n, uint32_t *v) { return fatGet(n, v); }
+  bool dbgFat(const uint32_t n, uint32_t * const v) { return fatGet(n, v); }
 
  private:
   // Allow SdBaseFile access to SdVolume private data.
@@ -164,20 +164,20 @@ class SdVolume {
   uint16_t rootDirEntryCount_;  // number of entries in FAT16 root dir
   uint32_t rootDirStart_;       // root start block for FAT16, cluster for FAT32
 
-  bool allocContiguous(uint32_t count, uint32_t *curCluster);
-  uint8_t blockOfCluster(uint32_t position) const { return (position >> 9) & (blocksPerCluster_ - 1); }
-  uint32_t clusterStartBlock(uint32_t cluster) const { return dataStartBlock_ + ((cluster - 2) << clusterSizeShift_); }
-  uint32_t blockNumber(uint32_t cluster, uint32_t position) const { return clusterStartBlock(cluster) + blockOfCluster(position); }
+  bool allocContiguous(const uint32_t count, uint32_t * const curCluster);
+  uint8_t blockOfCluster(const uint32_t position) const { return (position >> 9) & (blocksPerCluster_ - 1); }
+  uint32_t clusterStartBlock(const uint32_t cluster) const { return dataStartBlock_ + ((cluster - 2) << clusterSizeShift_); }
+  uint32_t blockNumber(const uint32_t cluster, const uint32_t position) const { return clusterStartBlock(cluster) + blockOfCluster(position); }
 
   cache_t* cache() { return &cacheBuffer_; }
   uint32_t cacheBlockNumber() const { return cacheBlockNumber_; }
 
   #if USE_MULTIPLE_CARDS
     bool cacheFlush();
-    bool cacheRawBlock(uint32_t blockNumber, bool dirty);
+    bool cacheRawBlock(const uint32_t blockNumber, const bool dirty);
   #else
     static bool cacheFlush();
-    static bool cacheRawBlock(uint32_t blockNumber, bool dirty);
+    static bool cacheRawBlock(const uint32_t blockNumber, const bool dirty);
   #endif
 
   // used by SdBaseFile write to assign cache to SD location
@@ -186,18 +186,18 @@ class SdVolume {
     cacheBlockNumber_  = blockNumber;
   }
   void cacheSetDirty() { cacheDirty_ |= CACHE_FOR_WRITE; }
-  bool chainSize(uint32_t beginCluster, uint32_t *size);
-  bool fatGet(uint32_t cluster, uint32_t *value);
-  bool fatPut(uint32_t cluster, uint32_t value);
-  bool fatPutEOC(uint32_t cluster) { return fatPut(cluster, 0x0FFFFFFF); }
+  bool chainSize(uint32_t cluster, uint32_t * const size);
+  bool fatGet(const uint32_t cluster, uint32_t * const value);
+  bool fatPut(const uint32_t cluster, const uint32_t value);
+  bool fatPutEOC(const uint32_t cluster) { return fatPut(cluster, 0x0FFFFFFF); }
   bool freeChain(uint32_t cluster);
-  bool isEOC(uint32_t cluster) const {
-    if (FAT12_SUPPORT && fatType_ == 12) return  cluster >= FAT12EOC_MIN;
+  bool isEOC(const uint32_t cluster) const {
+    if (FAT12_SUPPORT && fatType_ == 12) return cluster >= FAT12EOC_MIN;
     if (fatType_ == 16) return cluster >= FAT16EOC_MIN;
-    return  cluster >= FAT32EOC_MIN;
+    return cluster >= FAT32EOC_MIN;
   }
-  bool readBlock(uint32_t block, uint8_t *dst) { return sdCard_->readBlock(block, dst); }
-  bool writeBlock(uint32_t block, const uint8_t *dst) { return sdCard_->writeBlock(block, dst); }
+  bool readBlock(const uint32_t block, uint8_t * const dst) { return sdCard_->readBlock(block, dst); }
+  bool writeBlock(const uint32_t block, const uint8_t * const dst) { return sdCard_->writeBlock(block, dst); }
 };
 
 using MarlinVolume = SdVolume;
diff --git a/Marlin/src/sd/disk_io_driver.h b/Marlin/src/sd/disk_io_driver.h
index 3e2d688aea720..f1f49cf85f463 100644
--- a/Marlin/src/sd/disk_io_driver.h
+++ b/Marlin/src/sd/disk_io_driver.h
@@ -47,18 +47,18 @@ class DiskIODriver {
    *
    * \return true for success or false for failure.
    */
-  virtual bool readCSD(csd_t* csd) = 0;
+  virtual bool readCSD(csd_t * const csd) = 0;
 
   virtual bool readStart(const uint32_t block) = 0;
-  virtual bool readData(uint8_t* dst) = 0;
+  virtual bool readData(uint8_t * const dst) = 0;
   virtual bool readStop() = 0;
 
   virtual bool writeStart(const uint32_t block, const uint32_t) = 0;
   virtual bool writeData(const uint8_t* src) = 0;
   virtual bool writeStop() = 0;
 
-  virtual bool readBlock(uint32_t block, uint8_t* dst) = 0;
-  virtual bool writeBlock(uint32_t blockNumber, const uint8_t* src) = 0;
+  virtual bool readBlock(const uint32_t block, uint8_t * const dst) = 0;
+  virtual bool writeBlock(const uint32_t blockNumber, const uint8_t * const src) = 0;
 
   virtual uint32_t cardSize() = 0;