diff --git a/Grbl_Esp32/src/MachineConfig.cpp b/Grbl_Esp32/src/MachineConfig.cpp
index 67182c50..723bcb40 100644
--- a/Grbl_Esp32/src/MachineConfig.cpp
+++ b/Grbl_Esp32/src/MachineConfig.cpp
@@ -373,11 +373,6 @@ void MachineConfig::afterParse() {
         _coolant = new CoolantControl();
     }
 
-    if (_spi == nullptr) {
-        log_info("SPI config missing; building default SPI bus.");
-        _spi = new SPIBus();
-    }
-
     if (_probe == nullptr) {
         log_info("Probe config missing; building default probe.");
         _probe = new Probe();
diff --git a/Grbl_Esp32/src/Motors/TrinamicDriver.cpp b/Grbl_Esp32/src/Motors/TrinamicDriver.cpp
index 521658dc..108d9556 100644
--- a/Grbl_Esp32/src/Motors/TrinamicDriver.cpp
+++ b/Grbl_Esp32/src/Motors/TrinamicDriver.cpp
@@ -91,32 +91,36 @@ namespace Motors {
         config_message();
 
         auto spiConfig = MachineConfig::instance()->_spi;
+        if (spiConfig != nullptr) {
+            auto ssPin   = spiConfig->_ss.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
+            auto mosiPin = spiConfig->_mosi.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
+            auto sckPin  = spiConfig->_sck.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
+            auto misoPin = spiConfig->_miso.getNative(Pin::Capabilities::Input | Pin::Capabilities::Native);
 
-        auto ssPin   = spiConfig->_ss.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
-        auto mosiPin = spiConfig->_mosi.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
-        auto sckPin  = spiConfig->_sck.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
-        auto misoPin = spiConfig->_miso.getNative(Pin::Capabilities::Input | Pin::Capabilities::Native);
+            SPI.begin(sckPin, misoPin, mosiPin, ssPin);  // this will get called for each motor, but does not seem to hurt anything
 
-        SPI.begin(sckPin, misoPin, mosiPin, ssPin);  // this will get called for each motor, but does not seem to hurt anything
+            tmcstepper->begin();
 
-        tmcstepper->begin();
+            _has_errors = !test();  // Try communicating with motor. Prints an error if there is a problem.
 
-        _has_errors = !test();  // Try communicating with motor. Prints an error if there is a problem.
+            read_settings();  // pull info from settings
+            set_mode(false);
 
-        read_settings();  // pull info from settings
-        set_mode(false);
-
-        // After initializing all of the TMC drivers, create a task to
-        // display StallGuard data.  List == this for the final instance.
-        if (List == this) {
-            xTaskCreatePinnedToCore(readSgTask,    // task
-                                    "readSgTask",  // name for task
-                                    4096,          // size of task stack
-                                    NULL,          // parameters
-                                    1,             // priority
-                                    NULL,
-                                    0  // core
-            );
+            // After initializing all of the TMC drivers, create a task to
+            // display StallGuard data.  List == this for the final instance.
+            if (List == this) {
+                xTaskCreatePinnedToCore(readSgTask,    // task
+                                        "readSgTask",  // name for task
+                                        4096,          // size of task stack
+                                        NULL,          // parameters
+                                        1,             // priority
+                                        NULL,
+                                        0  // core
+                );
+            }
+        } else {
+            grbl_msg_sendf(CLIENT_SERIAL, MsgLevel::Info, "SPI bus is not available; cannot initialize TMC driver.");
+            _has_errors = true;
         }
     }
 
diff --git a/Grbl_Esp32/src/SDCard.cpp b/Grbl_Esp32/src/SDCard.cpp
index 1298b86e..02da8148 100644
--- a/Grbl_Esp32/src/SDCard.cpp
+++ b/Grbl_Esp32/src/SDCard.cpp
@@ -129,44 +129,48 @@ uint32_t sd_get_current_line_number() {
 uint8_t sd_state = SDCARD_IDLE;
 
 uint8_t get_sd_state(bool refresh) {
-    // Before we use the SD library, we *must* make sure SPI is properly initialized. Re-initialization 
+    // Before we use the SD library, we *must* make sure SPI is properly initialized. Re-initialization
     // fortunately doesn't change any of the settings.
     auto spiConfig = MachineConfig::instance()->_spi;
 
-    auto ssPin = spiConfig->_ss.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
-    auto mosiPin = spiConfig->_mosi.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
-    auto sckPin = spiConfig->_sck.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
-    auto misoPin = spiConfig->_miso.getNative(Pin::Capabilities::Input | Pin::Capabilities::Native);
+    if (spiConfig != nullptr) {
+        auto ssPin   = spiConfig->_ss.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
+        auto mosiPin = spiConfig->_mosi.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
+        auto sckPin  = spiConfig->_sck.getNative(Pin::Capabilities::Output | Pin::Capabilities::Native);
+        auto misoPin = spiConfig->_miso.getNative(Pin::Capabilities::Input | Pin::Capabilities::Native);
 
-    SPI.begin(sckPin, misoPin, mosiPin, ssPin);  // this will get called for each motor, but does not seem to hurt anything
+        SPI.begin(sckPin, misoPin, mosiPin, ssPin);  // this will get called for each motor, but does not seem to hurt anything
 
-    //no need to go further if SD detect is not correct
-    if (SDCardDetPin->get() != Pin::UNDEFINED) {
-        if (!((SDCardDetPin->get().read() == SDCARD_DET_VAL) ? true : false)) {
-            sd_state = SDCARD_NOT_PRESENT;
+        //no need to go further if SD detect is not correct
+        if (SDCardDetPin->get() != Pin::UNDEFINED) {
+            if (!((SDCardDetPin->get().read() == SDCARD_DET_VAL) ? true : false)) {
+                sd_state = SDCARD_NOT_PRESENT;
+                return sd_state;
+            }
+        }
+
+        //if busy doing something return state
+        if (!((sd_state == SDCARD_NOT_PRESENT) || (sd_state == SDCARD_IDLE))) {
             return sd_state;
         }
-    }
-
-    //if busy doing something return state
-    if (!((sd_state == SDCARD_NOT_PRESENT) || (sd_state == SDCARD_IDLE))) {
-        return sd_state;
-    }
-    if (!refresh) {
-        return sd_state;  //to avoid refresh=true + busy to reset SD and waste time
-    }
-
-    //SD is idle or not detected, let see if still the case
-    SD.end();
-    sd_state = SDCARD_NOT_PRESENT;
-    //using default value for speed ? should be parameter
-    //refresh content if card was removed
-    if (SD.begin((GRBL_SPI_SS == -1) ? SS : GRBL_SPI_SS, SPI, GRBL_SPI_FREQ, "/sd", 2)) {
-        if (SD.cardSize() > 0) {
-            sd_state = SDCARD_IDLE;
+        if (!refresh) {
+            return sd_state;  //to avoid refresh=true + busy to reset SD and waste time
         }
+
+        //SD is idle or not detected, let see if still the case
+        SD.end();
+        sd_state = SDCARD_NOT_PRESENT;
+        //using default value for speed ? should be parameter
+        //refresh content if card was removed
+        if (SD.begin((GRBL_SPI_SS == -1) ? SS : GRBL_SPI_SS, SPI, GRBL_SPI_FREQ, "/sd", 2)) {
+            if (SD.cardSize() > 0) {
+                sd_state = SDCARD_IDLE;
+            }
+        }
+        return sd_state;
+    } else {
+        return SDCARD_NOT_PRESENT;
     }
-    return sd_state;
 }
 
 uint8_t set_sd_state(uint8_t flag) {