diff --git a/board/boards/cuatro.h b/board/boards/cuatro.h
index 00c2cf2285..545f87da8b 100644
--- a/board/boards/cuatro.h
+++ b/board/boards/cuatro.h
@@ -12,7 +12,7 @@ static void cuatro_set_led(uint8_t color, bool enabled) {
       set_gpio_output(GPIOD, 15, !enabled);
       break;
     case LED_GREEN:
-      set_gpio_output(GPIOD, 14, !enabled);
+      set_gpio_output(GPIOB, 2, !enabled);
       break;
     case LED_BLUE:
       set_gpio_output(GPIOE, 2, !enabled);
@@ -71,12 +71,16 @@ static void cuatro_set_bootkick(BootState state) {
   //set_gpio_output(GPIOC, 12, state != BOOT_RESET);
 }
 
+static void cuatro_set_siren(bool enabled){
+  beeper_enable(enabled);
+}
+
 static void cuatro_init(void) {
   red_chiplet_init();
 
   // init LEDs as open drain
   set_gpio_output_type(GPIOE, 2, OUTPUT_TYPE_OPEN_DRAIN);
-  set_gpio_output_type(GPIOD, 14, OUTPUT_TYPE_OPEN_DRAIN);
+  set_gpio_output_type(GPIOB, 2, OUTPUT_TYPE_OPEN_DRAIN);
   set_gpio_output_type(GPIOD, 15, OUTPUT_TYPE_OPEN_DRAIN);
 
   // Power readout
@@ -120,6 +124,10 @@ static void cuatro_init(void) {
 
   // Clock source
   clock_source_init();
+
+  // Beeper
+  set_gpio_alternate(GPIOD, 14, GPIO_AF2_TIM4);
+  beeper_init();
 }
 
 board board_cuatro = {
@@ -143,7 +151,7 @@ board board_cuatro = {
   .read_current_mA = cuatro_read_current_mA,
   .set_fan_enabled = cuatro_set_fan_enabled,
   .set_ir_power = tres_set_ir_power,
-  .set_siren = unused_set_siren,
+  .set_siren = cuatro_set_siren,
   .set_bootkick = cuatro_set_bootkick,
   .read_som_gpio = tres_read_som_gpio
 };
diff --git a/board/drivers/beeper.h b/board/drivers/beeper.h
new file mode 100644
index 0000000000..0ae02ff5e6
--- /dev/null
+++ b/board/drivers/beeper.h
@@ -0,0 +1,26 @@
+
+#define BEEPER_COUNTER_OVERFLOW 25000U // 4kHz
+
+void beeper_enable(bool enabled) {
+  if (enabled) {
+    register_set_bits(&(TIM4->CCER), TIM_CCER_CC3E);
+  } else {
+    register_clear_bits(&(TIM4->CCER), TIM_CCER_CC3E);
+  }
+}
+
+void beeper_init(void) {
+  // Enable timer and auto-reload
+  register_set(&(TIM4->CR1), TIM_CR1_CEN | TIM_CR1_ARPE, 0x3FU);
+
+  // Set channel as PWM mode 1 and disable output
+  register_set_bits(&(TIM4->CCMR2), (TIM_CCMR2_OC3M_2 | TIM_CCMR2_OC3M_1 | TIM_CCMR2_OC3PE));
+  beeper_enable(false);
+
+  // Set max counter value and compare to get 50% duty
+  register_set(&(TIM4->CCR3), BEEPER_COUNTER_OVERFLOW / 2U, 0xFFFFU);
+  register_set(&(TIM4->ARR), BEEPER_COUNTER_OVERFLOW, 0xFFFFU);
+
+  // Update registers and clear counter
+  TIM4->EGR |= TIM_EGR_UG;
+}
diff --git a/board/stm32h7/board.h b/board/stm32h7/board.h
index e8ea23b252..6fbadcb633 100644
--- a/board/stm32h7/board.h
+++ b/board/stm32h7/board.h
@@ -10,6 +10,7 @@
 #include "drivers/fan.h"
 #include "stm32h7/llfan.h"
 #include "stm32h7/lldac.h"
+#include "drivers/beeper.h"
 #include "drivers/fake_siren.h"
 #include "drivers/clock_source.h"
 #include "boards/red.h"
diff --git a/board/stm32h7/peripherals.h b/board/stm32h7/peripherals.h
index b9a5861224..8b1cae2a68 100644
--- a/board/stm32h7/peripherals.h
+++ b/board/stm32h7/peripherals.h
@@ -126,6 +126,7 @@ void peripherals_init(void) {
   RCC->APB2ENR |= RCC_APB2ENR_TIM1EN;  // clock source timer
   RCC->APB1LENR |= RCC_APB1LENR_TIM2EN;  // main counter
   RCC->APB1LENR |= RCC_APB1LENR_TIM3EN;  // fan pwm
+  RCC->APB1LENR |= RCC_APB1LENR_TIM4EN;  // beeper source
   RCC->APB1LENR |= RCC_APB1LENR_TIM6EN;  // interrupt timer
   RCC->APB1LENR |= RCC_APB1LENR_TIM7EN;  // DMA trigger timer
   RCC->APB2ENR |= RCC_APB2ENR_TIM8EN;  // tick timer