diff --git a/drivers/issi/is31fl3733.c b/drivers/issi/is31fl3733.c
index c18ed7ca30..aa247f4e8a 100644
--- a/drivers/issi/is31fl3733.c
+++ b/drivers/issi/is31fl3733.c
@@ -75,10 +75,10 @@ uint8_t g_twi_transfer_buffer[20];
 // buffers and the transfers in IS31FL3733_write_pwm_buffer() but it's
 // probably not worth the extra complexity.
 uint8_t g_pwm_buffer[DRIVER_COUNT][192];
-bool g_pwm_buffer_update_required = false;
+bool g_pwm_buffer_update_required[DRIVER_COUNT] = { false };
 
 uint8_t g_led_control_registers[DRIVER_COUNT][24] = { { 0 }, { 0 } };
-bool g_led_control_registers_update_required = false;
+bool g_led_control_registers_update_required[DRIVER_COUNT] = { false };
 
 void IS31FL3733_write_register( uint8_t addr, uint8_t reg, uint8_t data )
 {
@@ -123,12 +123,13 @@ void IS31FL3733_write_pwm_buffer( uint8_t addr, uint8_t *pwm_buffer )
     }
 }
 
-void IS31FL3733_init( uint8_t addr )
+void IS31FL3733_init( uint8_t addr, uint8_t sync)
 {
     // In order to avoid the LEDs being driven with garbage data
     // in the LED driver's PWM registers, shutdown is enabled last.
     // Set up the mode and other settings, clear the PWM registers,
     // then disable software shutdown.
+    // Sync is passed so set it according to the datasheet.
 
     // Unlock the command register.
     IS31FL3733_write_register( addr, ISSI_COMMANDREGISTER_WRITELOCK, 0xC5 );
@@ -161,7 +162,7 @@ void IS31FL3733_init( uint8_t addr )
     // Set global current to maximum.
     IS31FL3733_write_register( addr, ISSI_REG_GLOBALCURRENT, 0xFF );
     // Disable software shutdown.
-    IS31FL3733_write_register( addr, ISSI_REG_CONFIGURATION, 0x01 );
+    IS31FL3733_write_register( addr, ISSI_REG_CONFIGURATION, (sync << 6) | 0x01 );
 
     // Wait 10ms to ensure the device has woken up.
     #ifdef __AVR__
@@ -179,7 +180,7 @@ void IS31FL3733_set_color( int index, uint8_t red, uint8_t green, uint8_t blue )
         g_pwm_buffer[led.driver][led.r] = red;
         g_pwm_buffer[led.driver][led.g] = green;
         g_pwm_buffer[led.driver][led.b] = blue;
-        g_pwm_buffer_update_required = true;
+        g_pwm_buffer_update_required[led.driver] = true;
     }
 }
 
@@ -218,35 +219,34 @@ void IS31FL3733_set_led_control_register( uint8_t index, bool red, bool green, b
         g_led_control_registers[led.driver][control_register_b] &= ~(1 << bit_b);
     }
 
-    g_led_control_registers_update_required = true;
+    g_led_control_registers_update_required[led.driver] = true;
 
 }
 
-void IS31FL3733_update_pwm_buffers( uint8_t addr1, uint8_t addr2 )
+void IS31FL3733_update_pwm_buffers( uint8_t addr, uint8_t index )
 {
-    if ( g_pwm_buffer_update_required )
+    if ( g_pwm_buffer_update_required[index] )
     {
         // Firstly we need to unlock the command register and select PG1
-        IS31FL3733_write_register( addr1, ISSI_COMMANDREGISTER_WRITELOCK, 0xC5 );
-        IS31FL3733_write_register( addr1, ISSI_COMMANDREGISTER, ISSI_PAGE_PWM );
+        IS31FL3733_write_register( addr, ISSI_COMMANDREGISTER_WRITELOCK, 0xC5 );
+        IS31FL3733_write_register( addr, ISSI_COMMANDREGISTER, ISSI_PAGE_PWM );
 
-        IS31FL3733_write_pwm_buffer( addr1, g_pwm_buffer[0] );
-        //IS31FL3733_write_pwm_buffer( addr2, g_pwm_buffer[1] );
+        IS31FL3733_write_pwm_buffer( addr, g_pwm_buffer[index] );
     }
-    g_pwm_buffer_update_required = false;
+    g_pwm_buffer_update_required[index] = false;
 }
 
-void IS31FL3733_update_led_control_registers( uint8_t addr1, uint8_t addr2 )
+void IS31FL3733_update_led_control_registers( uint8_t addr, uint8_t index )
 {
-    if ( g_led_control_registers_update_required )
+    if ( g_led_control_registers_update_required[index] )
     {
         // Firstly we need to unlock the command register and select PG0
-        IS31FL3733_write_register( addr1, ISSI_COMMANDREGISTER_WRITELOCK, 0xC5 );
-        IS31FL3733_write_register( addr1, ISSI_COMMANDREGISTER, ISSI_PAGE_LEDCONTROL );
+        IS31FL3733_write_register( addr, ISSI_COMMANDREGISTER_WRITELOCK, 0xC5 );
+        IS31FL3733_write_register( addr, ISSI_COMMANDREGISTER, ISSI_PAGE_LEDCONTROL );
         for ( int i=0; i<24; i++ )
         {
-            IS31FL3733_write_register(addr1, i, g_led_control_registers[0][i] );
-            //IS31FL3733_write_register(addr2, i, g_led_control_registers[1][i] );
+            IS31FL3733_write_register(addr, i, g_led_control_registers[index][i] );
         }
     }
+    g_led_control_registers_update_required[index] = false;
 }
diff --git a/drivers/issi/is31fl3733.h b/drivers/issi/is31fl3733.h
index 3d23b188aa..e117b25460 100644
--- a/drivers/issi/is31fl3733.h
+++ b/drivers/issi/is31fl3733.h
@@ -32,7 +32,7 @@ typedef struct is31_led {
 
 extern const is31_led g_is31_leds[DRIVER_LED_TOTAL];
 
-void IS31FL3733_init( uint8_t addr );
+void IS31FL3733_init( uint8_t addr, uint8_t sync );
 void IS31FL3733_write_register( uint8_t addr, uint8_t reg, uint8_t data );
 void IS31FL3733_write_pwm_buffer( uint8_t addr, uint8_t *pwm_buffer );
 
@@ -45,8 +45,8 @@ void IS31FL3733_set_led_control_register( uint8_t index, bool red, bool green, b
 // (eg. from a timer interrupt).
 // Call this while idle (in between matrix scans).
 // If the buffer is dirty, it will update the driver with the buffer.
-void IS31FL3733_update_pwm_buffers( uint8_t addr1, uint8_t addr2 );
-void IS31FL3733_update_led_control_registers( uint8_t addr1, uint8_t addr2 );
+void IS31FL3733_update_pwm_buffers( uint8_t addr, uint8_t index );
+void IS31FL3733_update_led_control_registers( uint8_t addr, uint8_t index );
 
 #define A_1  0x00
 #define A_2  0x01
diff --git a/quantum/led_matrix_drivers.c b/quantum/led_matrix_drivers.c
index 4ee509ee56..cb91821a40 100644
--- a/quantum/led_matrix_drivers.c
+++ b/quantum/led_matrix_drivers.c
@@ -53,16 +53,16 @@ static void init(void) {
         #endif
     #else
         #ifdef LED_DRIVER_ADDR_1
-            IS31FL3733_init(LED_DRIVER_ADDR_1);
+            IS31FL3733_init(LED_DRIVER_ADDR_1, 0 );
         #endif
         #ifdef LED_DRIVER_ADDR_2
-            IS31FL3733_init(LED_DRIVER_ADDR_2);
+            IS31FL3733_init(LED_DRIVER_ADDR_2, 0 );
         #endif
         #ifdef LED_DRIVER_ADDR_3
-            IS31FL3733_init(LED_DRIVER_ADDR_3);
+            IS31FL3733_init(LED_DRIVER_ADDR_3, 0 );
         #endif
         #ifdef LED_DRIVER_ADDR_4
-            IS31FL3733_init(LED_DRIVER_ADDR_4);
+            IS31FL3733_init(LED_DRIVER_ADDR_4, 0 );
         #endif
     #endif
 
diff --git a/quantum/rgb_matrix_drivers.c b/quantum/rgb_matrix_drivers.c
index 1d64dc9093..2a3aa9a5e0 100644
--- a/quantum/rgb_matrix_drivers.c
+++ b/quantum/rgb_matrix_drivers.c
@@ -34,7 +34,7 @@ static void init( void )
     IS31FL3731_init( DRIVER_ADDR_1 );
     IS31FL3731_init( DRIVER_ADDR_2 );
 #elif defined(IS31FL3733)
-    IS31FL3733_init( DRIVER_ADDR_1 );
+    IS31FL3733_init( DRIVER_ADDR_1, 0 );
 #else
     IS31FL3737_init( DRIVER_ADDR_1 );
 #endif
@@ -53,7 +53,8 @@ static void init( void )
 #ifdef IS31FL3731
     IS31FL3731_update_led_control_registers( DRIVER_ADDR_1, DRIVER_ADDR_2 );
 #elif defined(IS31FL3733)
-    IS31FL3733_update_led_control_registers( DRIVER_ADDR_1, DRIVER_ADDR_2 );
+    IS31FL3733_update_led_control_registers( DRIVER_ADDR_1, 0 );
+    IS31FL3733_update_led_control_registers( DRIVER_ADDR_2, 1 );
 #else
     IS31FL3737_update_led_control_registers( DRIVER_ADDR_1, DRIVER_ADDR_2 );
 #endif
@@ -74,7 +75,8 @@ const rgb_matrix_driver_t rgb_matrix_driver = {
 #elif defined(IS31FL3733)
 static void flush( void )
 {
-    IS31FL3733_update_pwm_buffers( DRIVER_ADDR_1, DRIVER_ADDR_2 );
+    IS31FL3733_update_pwm_buffers( DRIVER_ADDR_1, 0);
+    IS31FL3733_update_pwm_buffers( DRIVER_ADDR_2, 1);
 }
 
 const rgb_matrix_driver_t rgb_matrix_driver = {