diff --git a/src/main/application/buzzer.h b/src/main/application/buzzer.h
index 41b3a86..48353ef 100644
--- a/src/main/application/buzzer.h
+++ b/src/main/application/buzzer.h
@@ -67,6 +67,9 @@ bool buzzer_get_on( void );
 /**
  * @fn      buzzer_init( void )
  * @brief   Initializes the buzzer driver module.
+ * @note    Requires that the following modules have been initialized:
+ *          - `config`
+ *          - `blah`
  */
 void buzzer_init( void );
 
diff --git a/src/main/application/config.h b/src/main/application/config.h
index 26c8ca0..3d40c44 100644
--- a/src/main/application/config.h
+++ b/src/main/application/config.h
@@ -96,6 +96,9 @@ void config_get( config_t * config );
 /**
  * @fn      config_init( void )
  * @brief   Initializes the system's configuration.
+ * @note    Requires that the following modules have been initialized:
+ *          - `storage`
+ *          - `sys`
  */
 void config_init( void );
 
diff --git a/src/main/application/debug_port.h b/src/main/application/debug_port.h
index 169ab10..2376add 100644
--- a/src/main/application/debug_port.h
+++ b/src/main/application/debug_port.h
@@ -30,6 +30,7 @@
 /**
  * @fn      debug_port_init( void )
  * @brief   Initializes the debug port.
+ * @note    The debug port should be initialized after all other modules.
  */
 void debug_port_init( void );
 
diff --git a/src/main/application/io.h b/src/main/application/io.h
index de8a69e..aa3cba8 100644
--- a/src/main/application/io.h
+++ b/src/main/application/io.h
@@ -126,6 +126,9 @@ io_type_t io_get_type( io_pin_t pin );
 /**
  * @fn      io_init( void )
  * @brief   Initializes the keyer input / output module.
+ * @note    Requires that the following modules have been initialized:
+ *          - `config`
+ *          - `sys`
  */
 void io_init( void );
 
diff --git a/src/main/application/keyer.c b/src/main/application/keyer.c
index 6003a48..b1ee040 100644
--- a/src/main/application/keyer.c
+++ b/src/main/application/keyer.c
@@ -20,7 +20,6 @@
 #include "application/led.h"
 #include "application/wpm.h"
 #include "core/sys.h"
-#include "drivers/gpio.h"
 #include "utility/debug.h"
 #include "utility/types.h"
 #include "utility/utility.h"
diff --git a/src/main/application/keyer.h b/src/main/application/keyer.h
index c0809ee..6167975 100644
--- a/src/main/application/keyer.h
+++ b/src/main/application/keyer.h
@@ -89,6 +89,12 @@ keyer_paddle_mode_t keyer_get_paddle_mode( void );
 /**
  * @fn      keyer_init( void )
  * @brief   Initializes the keyer module.
+ * @note    Requires that the following modules have been initialized:
+ *          - `buzzer`
+ *          - `config`
+ *          - `io`
+ *          - `led`
+ *          - `sys`
  */
 void keyer_init( void );
 
diff --git a/src/main/application/led.h b/src/main/application/led.h
index 72f45b1..05f8ac0 100644
--- a/src/main/application/led.h
+++ b/src/main/application/led.h
@@ -49,6 +49,7 @@ bool led_get_on( led_t led );
 /**
  * @fn      led_init( void )
  * @brief   Initializes the LED driver module.
+ * @note    Requires that the `config` module has been initialized.
  */
 void led_init( void );
 
diff --git a/src/main/application/storage.h b/src/main/application/storage.h
index 0b7269f..22aa624 100644
--- a/src/main/application/storage.h
+++ b/src/main/application/storage.h
@@ -31,6 +31,7 @@ bool storage_get_config( config_version_t version, size_t size, void * config );
 /**
  * @fn      storage_init( void )
  * @brief   Initializes the storage module.
+ * @note    Does not currently depend on any other modules being initialized.
  */
 void storage_init( void );
 
diff --git a/src/main/core/main.c b/src/main/core/main.c
index 7031c1e..594bdda 100644
--- a/src/main/core/main.c
+++ b/src/main/core/main.c
@@ -207,8 +207,8 @@ static void init( void )
     led_init();
     io_init();
     buzzer_init();
-    debug_port_init();
     keyer_init();
+    debug_port_init();
 
     // Flash LEDs to indicate successful startup
     startup_display();
diff --git a/src/main/core/sys.h b/src/main/core/sys.h
index 15225a7..191a84a 100644
--- a/src/main/core/sys.h
+++ b/src/main/core/sys.h
@@ -120,6 +120,7 @@ tick_t sys_get_tick( void );
 /**
  * @fn      sys_init( void )
  * @brief   Initializes the system module.
+ * @note    `sys` should always be the first module initialized.
  */
 void sys_init( void );