diff --git a/keyboards/bastardkb/charybdis/charybdis.c b/keyboards/bastardkb/charybdis/charybdis.c
index 0ee5c3eed97..2251b247581 100644
--- a/keyboards/bastardkb/charybdis/charybdis.c
+++ b/keyboards/bastardkb/charybdis/charybdis.c
@@ -393,7 +393,6 @@ bool shutdown_kb(bool jump_to_bootloader) {
     rgblight_setrgb(RGB_RED);
 #endif // RGBLIGHT_ENABLE
 #ifdef RGB_MATRIX_ENABLE
-    void rgb_matrix_update_pwm_buffers(void);
     rgb_matrix_set_color_all(RGB_RED);
     rgb_matrix_update_pwm_buffers();
 #endif // RGB_MATRIX_ENABLE
diff --git a/keyboards/bastardkb/dilemma/dilemma.c b/keyboards/bastardkb/dilemma/dilemma.c
index 7c87fdcadd6..b406e265261 100644
--- a/keyboards/bastardkb/dilemma/dilemma.c
+++ b/keyboards/bastardkb/dilemma/dilemma.c
@@ -354,7 +354,6 @@ bool shutdown_kb(bool jump_to_bootloader) {
     rgblight_setrgb(RGB_RED);
 #endif // RGBLIGHT_ENABLE
 #ifdef RGB_MATRIX_ENABLE
-    void rgb_matrix_update_pwm_buffers(void);
     rgb_matrix_set_color_all(RGB_RED);
     rgb_matrix_update_pwm_buffers();
 #endif // RGB_MATRIX_ENABLE
diff --git a/keyboards/miiiw/blackio83/rev_0100/rev_0100.c b/keyboards/miiiw/blackio83/rev_0100/rev_0100.c
index 18f4c86510e..139bc1aaaef 100644
--- a/keyboards/miiiw/blackio83/rev_0100/rev_0100.c
+++ b/keyboards/miiiw/blackio83/rev_0100/rev_0100.c
@@ -165,7 +165,6 @@ uint32_t loop_10Hz(uint32_t trigger_time, void *cb_arg) {
             wait_ms(50);
             eeconfig_init();
     #ifdef RGB_MATRIX_ENABLE
-            extern void rgb_matrix_update_pwm_buffers(void);
             for(int i = 0; i < 5; i++) {
                 rgb_matrix_set_color_all(RGB_WHITE);
                 rgb_matrix_update_pwm_buffers();
diff --git a/quantum/rgb_matrix/rgb_matrix.h b/quantum/rgb_matrix/rgb_matrix.h
index 842a60c8b7e..33f7e06a639 100644
--- a/quantum/rgb_matrix/rgb_matrix.h
+++ b/quantum/rgb_matrix/rgb_matrix.h
@@ -212,6 +212,7 @@ void        rgb_matrix_decrease_speed_noeeprom(void);
 led_flags_t rgb_matrix_get_flags(void);
 void        rgb_matrix_set_flags(led_flags_t flags);
 void        rgb_matrix_set_flags_noeeprom(led_flags_t flags);
+void        rgb_matrix_update_pwm_buffers(void);
 
 #ifndef RGBLIGHT_ENABLE
 #    define eeconfig_update_rgblight_current eeconfig_update_rgb_matrix