diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index 44abf722f2..9704669d61 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -991,6 +991,20 @@ void setup() {
 
   SETUP_RUN(HAL_init());
 
+  // Early-disable MAX6675, as it can flood on SPI bus and prevent TMC and others to init correctly
+  // thermalManager.init() called too late to do this
+  #if HAS_MAX6675
+    #if ENABLED(HEATER_0_USES_MAX6675)
+      SET_OUTPUT(MAX6675_SS_PIN);               // Setup CS pin
+      WRITE(MAX6675_SS_PIN, HIGH);              // Disable TT_MAX6675
+    #endif
+    #if ENABLED(HEATER_1_USES_MAX6675)
+      SET_OUTPUT(MAX6675_SS2_PIN);            // Setup CS pin
+      WRITE(MAX6675_SS2_PIN, HIGH);           // Disable TT_MAX6675
+    #endif
+    DELAY_NS(100);                            // Ensure 100ns delay
+  #endif
+
   #if HAS_L64XX
     SETUP_RUN(L64xxManager.init());  // Set up SPI, init drivers
   #endif
diff --git a/Marlin/src/module/temperature.cpp b/Marlin/src/module/temperature.cpp
index b476b35593..666004a37a 100644
--- a/Marlin/src/module/temperature.cpp
+++ b/Marlin/src/module/temperature.cpp
@@ -2256,16 +2256,12 @@ void Temperature::disable_all_heaters() {
 
     #if COUNT_6675 > 1
       #define WRITE_MAX6675(V) do{ switch (hindex) { case 1: WRITE(MAX6675_SS2_PIN, V); break; default: WRITE(MAX6675_SS_PIN, V); } }while(0)
-      #define SET_OUTPUT_MAX6675() do{ switch (hindex) { case 1: SET_OUTPUT(MAX6675_SS2_PIN); break; default: SET_OUTPUT(MAX6675_SS_PIN); } }while(0)
     #elif HEATER_1_USES_MAX6675
       #define WRITE_MAX6675(V) WRITE(MAX6675_SS2_PIN, V)
-      #define SET_OUTPUT_MAX6675() SET_OUTPUT(MAX6675_SS2_PIN)
     #else
       #define WRITE_MAX6675(V) WRITE(MAX6675_SS_PIN, V)
-      #define SET_OUTPUT_MAX6675() SET_OUTPUT(MAX6675_SS_PIN)
     #endif
 
-    SET_OUTPUT_MAX6675();
     WRITE_MAX6675(LOW);  // enable TT_MAX6675
 
     DELAY_NS(100);       // Ensure 100ns delay