diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index 6b3dd0d7e64f2cf5934a112489b5c9b5c19a3ca7..7c1009e09c1cad3cd5d539ab82210639c966cf6f 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -667,6 +667,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/cardreader.cpp b/Marlin/cardreader.cpp
index 8bb22c8a2fdff2cd1175df83401a77628b82d5de..2fcd0c4b6839fb2cb898b8754a10611ec3cf30b8 100644
--- a/Marlin/cardreader.cpp
+++ b/Marlin/cardreader.cpp
@@ -195,7 +195,9 @@ void CardReader::initsd() {
   cardOK = false;
   if (root.isOpen()) root.close();
 
-  #if ENABLED(SDSLOW)
+  #if ENABLED(SDEXTRASLOW)
+    #define SPI_SPEED SPI_QUARTER_SPEED
+  #elif ENABLED(SDSLOW)
     #define SPI_SPEED SPI_HALF_SPEED
   #else
     #define SPI_SPEED SPI_FULL_SPEED
diff --git a/Marlin/configurator/config/Configuration.h b/Marlin/configurator/config/Configuration.h
index 4ba6dd2eaefec40d21b09856fdf3fc170cdb4528..ec7f0969db8cf8ead06744dcb43cf63d02a94628 100644
--- a/Marlin/configurator/config/Configuration.h
+++ b/Marlin/configurator/config/Configuration.h
@@ -666,6 +666,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/Felix/Configuration.h b/Marlin/example_configurations/Felix/Configuration.h
index 4f9ce10ce002d931c24f0f0e723893ee95fa5cd5..b5543e3d92bc659dc93d33ee7ce30bece9694908 100644
--- a/Marlin/example_configurations/Felix/Configuration.h
+++ b/Marlin/example_configurations/Felix/Configuration.h
@@ -649,6 +649,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/Felix/Configuration_DUAL.h b/Marlin/example_configurations/Felix/Configuration_DUAL.h
index d9586d7b2f668fdb6505e9d9109a580bf6bc91c0..672e05446fc919b4bb549b23146f096a89e85364 100644
--- a/Marlin/example_configurations/Felix/Configuration_DUAL.h
+++ b/Marlin/example_configurations/Felix/Configuration_DUAL.h
@@ -618,6 +618,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/Hephestos/Configuration.h b/Marlin/example_configurations/Hephestos/Configuration.h
index 3811129b71eb5ce8d3cff356c41b8746ac5d0ebf..c6fcee8371c3ea962be664d16e3589c091a9aeb8 100644
--- a/Marlin/example_configurations/Hephestos/Configuration.h
+++ b/Marlin/example_configurations/Hephestos/Configuration.h
@@ -659,6 +659,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = true; // set to true to invert the lo
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 #define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/K8200/Configuration.h b/Marlin/example_configurations/K8200/Configuration.h
index 5eec325e48c51549f3739e03f2b58c6cbf3d583d..5d4734ee36b8421aaf411542879b44930530dde5 100644
--- a/Marlin/example_configurations/K8200/Configuration.h
+++ b/Marlin/example_configurations/K8200/Configuration.h
@@ -654,6 +654,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/RepRapWorld/Megatronics/Configuration.h b/Marlin/example_configurations/RepRapWorld/Megatronics/Configuration.h
index 79d001a451ac4c3401251d0d07fd1be2095de005..6f7e7e1c74a93bdd3fde3b35658c7fd7f9f6c6c3 100644
--- a/Marlin/example_configurations/RepRapWorld/Megatronics/Configuration.h
+++ b/Marlin/example_configurations/RepRapWorld/Megatronics/Configuration.h
@@ -667,6 +667,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 #define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 #define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/RigidBot/Configuration.h b/Marlin/example_configurations/RigidBot/Configuration.h
index 105b0521ef8cb5c8fc324d5037b9d0d838a29bd1..2369b878f59d7c2856ac8d261e98e4b14d1a9388 100644
--- a/Marlin/example_configurations/RigidBot/Configuration.h
+++ b/Marlin/example_configurations/RigidBot/Configuration.h
@@ -653,6 +653,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/SCARA/Configuration.h b/Marlin/example_configurations/SCARA/Configuration.h
index e7b9f182d618008725ed560b427cf796bdc295f4..0738512ef2374097d08f7c41d49bc9b9b3f2083b 100644
--- a/Marlin/example_configurations/SCARA/Configuration.h
+++ b/Marlin/example_configurations/SCARA/Configuration.h
@@ -674,6 +674,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/TAZ4/Configuration.h b/Marlin/example_configurations/TAZ4/Configuration.h
index b264b36cad539545d8904ccaa4e23f617eaf1f62..cf52f9c3c1cd4bfa16823725a0ed0071e9776ac1 100644
--- a/Marlin/example_configurations/TAZ4/Configuration.h
+++ b/Marlin/example_configurations/TAZ4/Configuration.h
@@ -685,6 +685,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 #define ENCODER_PULSES_PER_STEP 2 // Increase if you have a high resolution encoder
 #define ENCODER_STEPS_PER_MENU_ITEM 1 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/WITBOX/Configuration.h b/Marlin/example_configurations/WITBOX/Configuration.h
index 1728d19b65bdb0281da84e596bcafd07e7423d13..720aff139e46698a882741ee9b6e11ef4d26e695 100644
--- a/Marlin/example_configurations/WITBOX/Configuration.h
+++ b/Marlin/example_configurations/WITBOX/Configuration.h
@@ -658,6 +658,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = true; // set to true to invert the lo
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 #define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/adafruit/ST7565/Configuration.h b/Marlin/example_configurations/adafruit/ST7565/Configuration.h
index 031cceb4f1c7f1cb5c4b41c1c1c939cb1eecb40e..3d72a5fd34ff83210f7f1a53869e3fb601622bd8 100644
--- a/Marlin/example_configurations/adafruit/ST7565/Configuration.h
+++ b/Marlin/example_configurations/adafruit/ST7565/Configuration.h
@@ -667,6 +667,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 #define SDSUPPORT // Enable SD Card Support in Hardware Console
 #define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/delta/biv2.5/Configuration.h b/Marlin/example_configurations/delta/biv2.5/Configuration.h
index ba2abe1cb6230f67e5d4eb47248f76e795bee244..fb77c1edaa1e2e8c2d605735ec31d109540490c3 100644
--- a/Marlin/example_configurations/delta/biv2.5/Configuration.h
+++ b/Marlin/example_configurations/delta/biv2.5/Configuration.h
@@ -788,6 +788,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = true; // set to true to invert the lo
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/delta/generic/Configuration.h b/Marlin/example_configurations/delta/generic/Configuration.h
index c5250811dda40a5bf9b92bb623c6f3a05ff0bfdd..7a6bf66e1da750317ac438f0635a24cf7cc3b293 100644
--- a/Marlin/example_configurations/delta/generic/Configuration.h
+++ b/Marlin/example_configurations/delta/generic/Configuration.h
@@ -789,6 +789,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = true; // set to true to invert the lo
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/delta/kossel_mini/Configuration.h b/Marlin/example_configurations/delta/kossel_mini/Configuration.h
index 2c8c28310f9cee4b29b09df5bff562e6347f4bf4..5f47f1baa4e6da535a95210cf1ba997bad2d3864 100644
--- a/Marlin/example_configurations/delta/kossel_mini/Configuration.h
+++ b/Marlin/example_configurations/delta/kossel_mini/Configuration.h
@@ -793,6 +793,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/delta/kossel_pro/Configuration.h b/Marlin/example_configurations/delta/kossel_pro/Configuration.h
index 703e07d84ac4bb198ab2f3463c605be972cb0ce6..b484a2dccf9a9bed16ea84b27b6ce5188fc95f7a 100644
--- a/Marlin/example_configurations/delta/kossel_pro/Configuration.h
+++ b/Marlin/example_configurations/delta/kossel_pro/Configuration.h
@@ -784,6 +784,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 #define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/makibox/Configuration.h b/Marlin/example_configurations/makibox/Configuration.h
index b5fb7567ed6d067152b9296522a132065b5d1be4..7dc984e71c0277e9ded8d9d907c8b7f6be0626a5 100644
--- a/Marlin/example_configurations/makibox/Configuration.h
+++ b/Marlin/example_configurations/makibox/Configuration.h
@@ -669,6 +669,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 #define SDSUPPORT // Enable SD Card Support in Hardware Console
 #define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking
diff --git a/Marlin/example_configurations/tvrrug/Round2/Configuration.h b/Marlin/example_configurations/tvrrug/Round2/Configuration.h
index 4e349dec4066d57126f756e5f3a02de87a921f1f..eee2edc173961c752ffb73302d1f0c573cd62662 100644
--- a/Marlin/example_configurations/tvrrug/Round2/Configuration.h
+++ b/Marlin/example_configurations/tvrrug/Round2/Configuration.h
@@ -661,6 +661,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = true; // set to true to invert the lo
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
 //#define SDSUPPORT // Enable SD Card Support in Hardware Console
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
+//#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
 //#define ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder
 //#define ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking