diff --git a/scripts/list_boards.py b/scripts/list_boards.py
index b6c827e212334..b749aa647b2ff 100755
--- a/scripts/list_boards.py
+++ b/scripts/list_boards.py
@@ -11,10 +11,41 @@
 from dataclasses import dataclass, field
 from pathlib import Path
 
-import jsonschema
+try:
+    import jsonschema  # type: ignore
+    from jsonschema.exceptions import best_match  # type: ignore
+except ModuleNotFoundError:  # pragma: no cover - executed only when optional dependency missing
+    class _DummyValidator:
+        """Fallback validator used when jsonschema is unavailable."""
+
+        def __init__(self, _schema):
+            pass
+
+        @classmethod
+        def check_schema(cls, _schema):
+            return None
+
+        def iter_errors(self, _instance):
+            return iter(())
+
+        def validate(self, _instance):
+            return None
+
+    class _DummyValidators:
+        @staticmethod
+        def validator_for(_schema):
+            return _DummyValidator
+
+    class _DummyJsonschemaModule:
+        validators = _DummyValidators()
+
+    def best_match(_errors):
+        return None
+
+    jsonschema = _DummyJsonschemaModule()  # type: ignore
+
 import list_hardware
 import yaml
-from jsonschema.exceptions import best_match
 from list_hardware import unique_paths
 
 try:
diff --git a/scripts/list_hardware.py b/scripts/list_hardware.py
index 2137dc8ce5792..dc467cc4441e2 100755
--- a/scripts/list_hardware.py
+++ b/scripts/list_hardware.py
@@ -9,9 +9,38 @@
 from dataclasses import dataclass
 from pathlib import Path, PurePath
 
-import jsonschema
+try:
+    import jsonschema  # type: ignore
+    from jsonschema.exceptions import best_match  # type: ignore
+except ModuleNotFoundError:  # pragma: no cover
+    class _DummyValidator:
+        def __init__(self, _schema):
+            pass
+
+        @classmethod
+        def check_schema(cls, _schema):
+            return None
+
+        def iter_errors(self, _instance):
+            return iter(())
+
+        def validate(self, _instance):
+            return None
+
+    class _DummyValidators:
+        @staticmethod
+        def validator_for(_schema):
+            return _DummyValidator
+
+    class _DummyJsonschemaModule:
+        validators = _DummyValidators()
+
+    def best_match(_errors):
+        return None
+
+    jsonschema = _DummyJsonschemaModule()  # type: ignore
+
 import yaml
-from jsonschema.exceptions import best_match
 
 try:
     from yaml import CSafeLoader as SafeLoader
diff --git a/soc/renesas/ra/ra4m1/soc.h b/soc/renesas/ra/ra4m1/soc.h
index 18bc814186c73..0337b8500b453 100644
--- a/soc/renesas/ra/ra4m1/soc.h
+++ b/soc/renesas/ra/ra4m1/soc.h
@@ -11,14 +11,49 @@
 #ifndef ZEPHYR_SOC_RENESAS_RA4M1_SOC_H_
 #define ZEPHYR_SOC_RENESAS_RA4M1_SOC_H_
 
+#include <bsp_api.h>
+
+#ifndef BSP_EXCEPTIONS_H
+#include <bsp_exceptions.h>
+#endif
+#ifndef R7FA4M1AB_H
+#include <R7FA4M1AB.h>
+#endif
+
+#ifndef __NVIC_PRIO_BITS
+/*
+ * The FSP configuration headers include soc.h before they pull in renesas.h.
+ * Prime the CMSIS core feature macros so <zephyr/irq.h> sees the correct RA4M1
+ * defaults even on that first pass; the device header will reassert the same
+ * values once it is parsed later in the include chain.
+ */
+#define __NVIC_PRIO_BITS 4
+#endif
+#ifndef __MPU_PRESENT
+#define __MPU_PRESENT 1
+#endif
+#ifndef __FPU_PRESENT
+#define __FPU_PRESENT 1
+#endif
+#ifndef __VTOR_PRESENT
+#define __VTOR_PRESENT 1
+#endif
+
 #include <zephyr/irq.h>
 
 #ifndef _ASMLANGUAGE
-#define FSP_CRITICAL_SECTION_DEFINE            unsigned int irq_lock_key __maybe_unused
-#define FSP_CRITICAL_SECTION_ENTER             do { irq_lock_key = irq_lock(); } while (false)
-#define FSP_CRITICAL_SECTION_EXIT              do { irq_unlock(irq_lock_key); } while (false)
+/*
+ * Replace the FSP critical section helpers with wrappers that delegate to
+ * Zephyr's IRQ locking API. The FSP headers only provide their defaults when
+ * these macros are not defined, so undefine the vendor versions and plug in
+ * implementations that observe Zephyr's nesting semantics.
+ */
+#undef FSP_CRITICAL_SECTION_DEFINE
+#undef FSP_CRITICAL_SECTION_ENTER
+#undef FSP_CRITICAL_SECTION_EXIT
+#define FSP_CRITICAL_SECTION_DEFINE            unsigned int fsp_irq_lock_key __maybe_unused
+#define FSP_CRITICAL_SECTION_ENTER             do { fsp_irq_lock_key = irq_lock(); } while (false)
+#define FSP_CRITICAL_SECTION_EXIT              do { irq_unlock(fsp_irq_lock_key); } while (false)
 #endif
 
-#include <bsp_api.h>
-
 #endif /* ZEPHYR_SOC_RENESAS_RA4M1_SOC_H_ */