diff --git a/semestralka_2/src/bin/main.rs b/semestralka_2/src/bin/main.rs
index 93e831e..8d7ae4a 100644
--- a/semestralka_2/src/bin/main.rs
+++ b/semestralka_2/src/bin/main.rs
@@ -20,6 +20,7 @@ use dma_gpio::config::{
 use dma_gpio::hw_uart_pc::{driver::uart_task, usart1};
 use dma_gpio::wakeup::iwdg::{clear_wakeup_flags, init_watchdog};
 use dma_gpio::sleep::shutdown::enter_shutdown;
+use dma_gpio::sleep::standby::enter_standby_with_sram2_retention;
 use {defmt_rtt as _, panic_probe as _};
 
 bind_interrupts!(struct Irqs {
@@ -64,12 +65,12 @@ async fn main(spawner: Spawner) {
     // MAIN LOOP
     Timer::after(Duration::from_millis(500)).await;
 
-    // init_watchdog(p.IWDG).await;
+    init_watchdog(p.IWDG).await;
     Timer::after(Duration::from_millis(10)).await;
 
     loop {
         info!("entering shutdown");
-        enter_shutdown();
+        enter_standby_with_sram2_retention();
         cortex_m::asm::wfi();
         yield_now().await;
     }
diff --git a/semestralka_2/src/sleep/standby.rs b/semestralka_2/src/sleep/standby.rs
index f1374f8..3c4ad48 100644
--- a/semestralka_2/src/sleep/standby.rs
+++ b/semestralka_2/src/sleep/standby.rs
@@ -11,3 +11,32 @@ pub fn enter_standby() -> ! {
     
     cortex_m::asm::udf(); // never happen marker
 }
+
+pub fn enter_standby_with_sram2_retention() -> ! {
+    sram2_retention();
+    enter_standby();
+}
+
+pub fn sram2_retention() {
+    unsafe extern "C" {
+        fn HAL_PWREx_EnableSRAM2ContentStandbyRetention(sram2_pages: u32);
+    }
+
+    unsafe {
+        // 0x60 = PWR_SRAM2_FULL_STANDBY = PWR_CR1_RRSB1 | PWR_CR1_RRSB2
+        // See: STM32U5xx HAL: stm32u5xx_hal_pwr_ex.h line 227
+        //      CMSIS: PWR_CR1_RRSB1=0x20, PWR_CR1_RRSB2=0x40
+        HAL_PWREx_EnableSRAM2ContentStandbyRetention(0x60);
+    }
+}
+
+pub fn disable_sram2_retention() {
+    unsafe extern "C" {
+        fn HAL_PWREx_DisableSRAM2ContentStandbyRetention(sram2_pages: u32);
+    }
+
+    unsafe {
+        // Disable full SRAM2 retention
+        HAL_PWREx_DisableSRAM2ContentStandbyRetention(0x60);
+    }
+}