the usual malarkey

Marlin/src/sd/cardreader.cpp

@@ -472,47 +472,49 @@ void CardReader::mount() {
 #endif
 
 void CardReader::manage_media() {
-  static bool first_mount = true;     // Check first successful mount
-  static uint8_t prev_stat = 2;       // First call, no prior state
-  uint8_t stat = uint8_t(IS_SD_INSERTED());
-  if (stat == prev_stat) return;
+  static struct {
+    uint8_t prev:2;                   // First call, no prior state
+    bool did1st:1;
+  } stat = { 2, false };              // 2=first
 
-  DEBUG_ECHOLNPGM("SD: Status changed from ", prev_stat, " to ", stat);
+  uint8_t curr = uint8_t(IS_SD_INSERTED()); // 1=full 0=empty
+  if (curr == stat.prev) return;      // Neither changed nor first call?
 
   flag.workDirIsRoot = true;          // Return to root on mount/release
 
   if (ui.detected()) {
 
-    uint8_t old_stat = prev_stat;
-    prev_stat = stat;                 // Change now to prevent re-entry
+    const uint8_t old_stat = stat.prev;
+    stat.prev = curr;                 // Change now to prevent re-entry
 
-    if (stat) {                       // Media Inserted
+    if (curr) {                       // Media Inserted
       safe_delay(500);                // Some boards need a delay to get settled
-      if (TERN1(SD_IGNORE_AT_STARTUP, old_stat != 2))
+      if (TERN1(SD_IGNORE_AT_STARTUP, stat.did1st))
         mount();                      // Try to mount the media
       #if MB(FYSETC_CHEETAH, FYSETC_CHEETAH_V12, FYSETC_AIO_II)
         reset_stepper_drivers();      // Workaround for Cheetah bug
       #endif
-      if (!isMounted()) stat = 0;     // Not mounted?
+      if (!isMounted()) curr = 0;     // Not mounted?
     }
     else {
       #if PIN_EXISTS(SD_DETECT)
-        release();                    // Card is released
+        release();                    // Card is released (or first init)
       #endif
     }
 
-    ui.media_changed(old_stat, stat); // Update the UI
+    DEBUG_ECHOLNPGM("SD: Status changed from ", old_stat, " to ", curr);
+    ui.media_changed(old_stat, curr); // Update the UI
 
-    if (stat) {
+    if (curr) {
       TERN_(SDCARD_EEPROM_EMULATION, settings.first_load());
-      if (first_mount) {              // First mount?
+      if (!stat.did1st) {             // First mount handled?
         DEBUG_ECHOLNPGM("First mount.");
+        stat.did1st = true;           // Set did-first-mount flag
         #if ENABLED(POWER_LOSS_RECOVERY)
           recovery.check();           // Check for PLR file. (If not there then call autofile_begin)
         #elif DISABLED(NO_SD_AUTOSTART)
           autofile_begin();           // Look for auto0.g on the next loop
         #endif
-        first_mount = false;          // clear first mount flag
       }
     }
   }