diff --git a/docs/software_requirements/system_initialization.sdoc b/docs/software_requirements/system_initialization.sdoc
index 1002edf..cd40579 100644
--- a/docs/software_requirements/system_initialization.sdoc
+++ b/docs/software_requirements/system_initialization.sdoc
@@ -10,3 +10,293 @@ IMPORT_FROM_FILE: software_requirements.sgra
 TBD
 
 [/FREETEXT]
+
+[SECTION]
+TITLE: Interface Requirements
+
+[FREETEXT]
+
+TBD
+
+[/FREETEXT]
+
+[REQUIREMENT]
+UID: ZEP-127
+STATUS: Draft
+TYPE: Interface
+COMPONENT: System Initialization
+TITLE: Build-time Registration for System Initialization Notifications
+STATEMENT: >>>
+The Zephyr RTOS shall expose an interface to build-time registration for the following system initialization notifications:
+
+- Pre-CPU Architecture Initialization
+- Pre-Kernel Initialization
+- Post-Kernel Initialized
+- Application Initialization
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-146
+
+[REQUIREMENT]
+UID: ZEP-143
+STATUS: Draft
+TYPE: Interface
+COMPONENT: System Initialization
+TITLE: Build-time Registration for SMP-Initialized Notification
+STATEMENT: >>>
+Where the Symmetric Multi-Processing feature is enabled,
+
+the Zephyr RTOS shall expose an interface to build-time registration for the following system initialization notifications:
+
+- Symmetric Multi-Processing Initialized.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-146
+
+[/SECTION]
+
+[SECTION]
+TITLE: Functional Requirements
+
+[FREETEXT]
+
+TBD
+
+[/FREETEXT]
+
+[REQUIREMENT]
+UID: ZEP-128
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Sustain hardware watchdog inherited from preceding executable
+STATEMENT: >>>
+Where the Zephyr RTOS inherits an active hardware watchdog that cannot be reconfigured,
+
+the Zephyr RTOS shall sustain the active hardware watchdog.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-129
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Initial CPU stack usage kept within published limits
+STATEMENT: >>>
+The Zephyr RTOS shall use no more than the published amount of the initial CPU stack.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-130
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Preceding executable data availability
+STATEMENT: >>>
+While the Zephyr RTOS is in any system initialization phase,
+
+the Zephyr RTOS shall allow read access to the data provided by the preceding executable.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-131
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Initialization follows component dependency order
+STATEMENT: >>>
+The Zephyr RTOS shall initialize the system following the order of component dependencies.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-138
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Initialization ends with call to `main(void)`
+STATEMENT: >>>
+When all of the following has been established,
+
+the Zephyr RTOS shall call the C function `main(void)` on the system initialization stack:
+
+- each C++ static object has been initialized; and
+- each SMP context has been initialized; and
+- each System Initialization notification has been published; and
+- each memory access protection has been established.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-139
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Return value of `int main(void)` ignored
+STATEMENT: >>>
+The Zephyr RTOS shall explicitly ignore the return value of the call to `int main(void)`.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-140
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Code Coverage Data Dumped Upon Return from `main()`
+STATEMENT: >>>
+While the Zephyr RTOS shutdown sequence has not begun,
+
+When the call to `main(void)` returns,
+
+the Zephyr RTOS shall dump code coverage data.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-141
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: System Shutdown Disables Interrupts
+STATEMENT: >>>
+When the System Shutdown is entered,
+
+the Zephyr RTOS shall disable all interrupts.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-142
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Shutdown ends in empty infinite loop.
+STATEMENT: >>>
+When the System Shutdown sequence is completed,
+
+the Zephyr RTOS shall spin in an empty infinite loop.
+<<<
+
+[SECTION]
+TITLE: Initialization Notifications
+
+[FREETEXT]
+
+TBD
+
+[/FREETEXT]
+
+[REQUIREMENT]
+UID: ZEP-137
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Initialization Notifications given in Registration Priority Order
+STATEMENT: >>>
+The Zephyr RTOS shall publish notifications for an event following the notification priority indicated in the event registration.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-145
+
+[REQUIREMENT]
+UID: ZEP-132
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Pre-CPU Architecture Initialization Notification
+STATEMENT: >>>
+While the CPU Architecture-specific initialization has not begun,
+
+When the C language execution environment has been initialized,
+
+the Zephyr RTOS shall publish a notification to each component registered for this event notification.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-135
+
+[REQUIREMENT]
+UID: ZEP-133
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Pre-Kernel Initialization Notification
+STATEMENT: >>>
+While the RTOS Kernel initialization has not begun,
+
+When the CPU Architecture has been initialized,
+
+the Zephyr RTOS shall publish a notification to each component registered for the Pre-Kernel Initialization event notification.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-135
+
+[REQUIREMENT]
+UID: ZEP-134
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Post-Kernel Initialization Notification
+STATEMENT: >>>
+While the C++ static objects have not been initialized,
+
+When the RTOS Kernel initialization is complete,
+
+the Zephyr RTOS shall publish a notification to each component registered for the Post-Kernel Initialization event notification.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-135
+
+[REQUIREMENT]
+UID: ZEP-135
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Application Initialization Notification
+STATEMENT: >>>
+While the CPU memory coherence has not been established,
+
+When all C++ static objects have been initialized,
+
+the Zephyr RTOS shall publish a notification to each component registered for the Application Initialization event notification.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-145
+
+[REQUIREMENT]
+UID: ZEP-136
+STATUS: Draft
+TYPE: Functional
+COMPONENT: System Initialization
+TITLE: Symmetric Multi-Processing Initialized Notification
+STATEMENT: >>>
+Where the Symmetric Multi-Processing feature is enabled,
+
+Where the Non-Delayed SMP Initialization feature is enabled,
+
+While the Zephyr RTOS is in the initialization state,
+
+When the SMP initialization is complete,
+
+the Zephyr RTOS shall publish a notification to each component registered for the SMP Initialized notification event.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-135
+
+[/SECTION]
+
+[/SECTION]
+
+[SECTION]
+TITLE: Non-Functional Requirements
+
+[FREETEXT]
+
+TBD
+
+[/FREETEXT]
+
+[/SECTION]
diff --git a/docs/system_requirements/index.sdoc b/docs/system_requirements/index.sdoc
index dd33b1a..e0a9a9f 100644
--- a/docs/system_requirements/index.sdoc
+++ b/docs/system_requirements/index.sdoc
@@ -86,6 +86,51 @@ USER_STORY: >>>
 As a Zephyr RTOS user I want errors and exceptions to handled and react according to my applications requirements (e.g. reach/establish the applications safety state).
 <<<
 
+[SECTION]
+TITLE: System Initialization
+
+[FREETEXT]
+TBD
+[/FREETEXT]
+
+[REQUIREMENT]
+UID: ZEP-144
+STATUS: Draft
+TYPE: High Level
+COMPONENT: System Initialization
+TITLE: Extensible System Initialization
+STATEMENT: >>>
+The Zephyr RTOS initialization sequence shall be extensible.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-145
+STATUS: Draft
+TYPE: High Level
+COMPONENT: System Initialization
+TITLE: System Initialization Hooks
+STATEMENT: >>>
+The Zephyr RTOS shall execute registered initialization hooks at the requested point of the System Initialization sequence.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-144
+
+[REQUIREMENT]
+UID: ZEP-146
+STATUS: Draft
+TYPE: High Level
+COMPONENT: System Initialization
+TITLE: Build Time Registration of System Initialization Hooks
+STATEMENT: >>>
+The Zephyr RTOS shall expose an interface for build-time registration of an initialization hook to be executed at a specific point in the system initialization sequence.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-144
+
+[/SECTION]
+
 [REQUIREMENT]
 UID: ZEP-38
 STATUS: Draft