diff --git a/apps/exam_pop_up_controller.cpp b/apps/exam_pop_up_controller.cpp
index 47ab4629b..7e8736a74 100644
--- a/apps/exam_pop_up_controller.cpp
+++ b/apps/exam_pop_up_controller.cpp
@@ -58,10 +58,9 @@ ExamPopUpController::ContentView::ContentView(Responder * parentResponder) :
     AppsContainer * container = (AppsContainer *)controller->app()->container();
     if (controller->isActivatingExamMode()) {
       container->reset();
-      Ion::LED::setBlinking(0.5, true, false, false);
-      Ion::LED::setLockState(true);
+      Ion::LED::setColor(KDColorRed);
+      Ion::LED::setBlinking(1.0f, 0.1f);
     } else {
-      Ion::LED::setLockState(false);
       Ion::LED::setColor(KDColorBlack);
     }
     container->refreshPreferences();
diff --git a/ion/include/ion/led.h b/ion/include/ion/led.h
index b2d40cad7..dfb69c420 100644
--- a/ion/include/ion/led.h
+++ b/ion/include/ion/led.h
@@ -6,16 +6,9 @@
 namespace Ion {
 namespace LED {
 
+KDColor getColor();
 void setColor(KDColor c);
-void setBlinking(float blinkLength, bool red, bool green, bool blue);
-void setCharging(bool isPluggedIn, bool isCharging);
-
-/*
- * This is just a flag to see if we should mess with the LEDs on our own.
- * Especially useful for keeping the LED blinking while in exam mode.
- */
-bool getLockState();
-void setLockState(bool state);
+void setBlinking(float period, float dutyCycle);
 
 }
 }
diff --git a/ion/src/device/device.cpp b/ion/src/device/device.cpp
index 485fc6ca3..d23dd35d9 100644
--- a/ion/src/device/device.cpp
+++ b/ion/src/device/device.cpp
@@ -169,7 +169,7 @@ void initPeripherals() {
   SWD::Device::init();
 }
 
-void shutdownPeripherals() {
+void shutdownPeripherals(bool keepLEDAwake) {
   SWD::Device::shutdown();
   Console::Device::shutdown();
 #if USE_SD_CARD
@@ -177,7 +177,9 @@ void shutdownPeripherals() {
 #endif
   USB::Device::shutdown();
   Battery::Device::shutdown();
-  LED::Device::shutdown();
+  if (!keepLEDAwake) {
+    LED::Device::shutdown();
+  }
   Keyboard::Device::shutdown();
   Backlight::Device::shutdown();
   Display::Device::shutdown();
@@ -279,16 +281,33 @@ void initClocks() {
   RCC.APB2ENR()->set(apb2enr);
 }
 
-void shutdownClocks() {
+void shutdownClocks(bool keepLEDAwake) {
   // APB2 bus
   RCC.APB2ENR()->set(0x00008000); // Reset value
 
-  // APB1
-  RCC.APB1ENR()->set(0x00000402);
-  RCC.APB1LPENR()->setTIM3LPEN(true); // Keep the LED going
+  if (keepLEDAwake) {
+    /* TODO: enter sleep mode even if the LED is used and enable LED in low
+     * power mode. */
+    // Keep the LED going: peripheral clock enable in low power mode register
+    /*RCC.APB1LPENR()->setTIM3LPEN(true);
+    RCC.AHB1LPENR()->setGPIOBLPEN(true);
+    RCC.AHB1LPENR()->setGPIOCLPEN(true);*/
 
-  // AHB1 bus
-  RCC.AHB1ENR()->set(0); // Reset value
+    // APB1
+    class RCC::APB1ENR apb1enr(0x00000400);
+    apb1enr.setTIM3EN(true);
+    RCC.APB1ENR()->set(apb1enr);
+    // AHB1 bus
+    class RCC::AHB1ENR ahb1enr(0); // Reset value
+    ahb1enr.setGPIOBEN(true);
+    ahb1enr.setGPIOCEN(true);
+    RCC.AHB1ENR()->set(ahb1enr);
+  } else {
+    // APB1
+    RCC.APB1ENR()->set(0x00000400);
+    // AHB1 bus
+    RCC.AHB1ENR()->set(0); // Reset value
+  }
 
   RCC.AHB3ENR()->setFSMCEN(false);
 }
diff --git a/ion/src/device/device.h b/ion/src/device/device.h
index 16af422b6..a95bf85e7 100644
--- a/ion/src/device/device.h
+++ b/ion/src/device/device.h
@@ -14,9 +14,9 @@ void coreReset();
 void jumpReset();
 
 void initPeripherals();
-void shutdownPeripherals();
+void shutdownPeripherals(bool keepLEDAwake = false);
 void initClocks();
-void shutdownClocks();
+void shutdownClocks(bool keepLEDAwake = false);
 
 /* The serial number is 96 bits long. That's equal to 16 digits in base 64. We
  * expose a convenient "copySerialNumber" routine which can be called without
diff --git a/ion/src/device/led.cpp b/ion/src/device/led.cpp
index 3557ffe79..26cce0243 100644
--- a/ion/src/device/led.cpp
+++ b/ion/src/device/led.cpp
@@ -6,35 +6,32 @@
 
 // Public Ion::LED methods
 
-void Ion::LED::setColor(KDColor c) {
-  if (getLockState()) {
-    return;
-  }
+static KDColor sLedColor = KDColorBlack;
 
-  initTimer(Ion::LED::Device::Mode::PWM);
+KDColor Ion::LED::getColor() {
+  return sLedColor;
+}
+
+void Ion::LED::setColor(KDColor c) {
+  sLedColor = c;
 
   Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::RED, true);
   Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::GREEN, true);
   Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::BLUE, true);
 
-  TIM3.CCR2()->set(Device::dutyCycleForUInt8(c.red()));
-  TIM3.CCR3()->set(Device::dutyCycleForUInt8(c.blue()));
-  TIM3.CCR4()->set(Device::dutyCycleForUInt8(c.green()));
+  constexpr float maxColorValue = (float)((1 << 8) -1);
+  Device::setPeriodAndDutyCycles(Device::Mode::PWM, c.red()/maxColorValue, c.green()/maxColorValue, c.blue()/maxColorValue);
 }
 
-void Ion::LED::setBlinking(float blinkPeriod, bool red, bool green, bool blue) {
-  if (getLockState()) {
-    return;
-  }
+void Ion::LED::setBlinking(float period, float dutyCycle) {
+  Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::RED, sLedColor.red() > 0);
+  Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::GREEN, sLedColor.green() > 0);
+  Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::BLUE, sLedColor.blue() > 0);
 
-  initTimer(Ion::LED::Device::Mode::BLINK, blinkPeriod);
-
-  Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::RED, red);
-  Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::GREEN, green);
-  Ion::LED::Device::setColorStatus(Ion::LED::Device::Color::BLUE, blue);
+  Device::setPeriodAndDutyCycles(Device::Mode::BLINK, dutyCycle, dutyCycle, dutyCycle, period);
 }
 
-void Ion::LED::setCharging(bool isPluggedIn, bool isCharging) {
+/*void Ion::LED::setCharging(bool isPluggedIn, bool isCharging) {
   if (!isPluggedIn) {
     Ion::LED::setColor(KDColorBlack);
   }
@@ -46,17 +43,7 @@ void Ion::LED::setCharging(bool isPluggedIn, bool isCharging) {
       Ion::LED::setColor(KDColorGreen);
     }
   }
-}
-
-static bool lockState = false;
-
-bool Ion::LED::getLockState() {
-  return lockState;
-}
-
-void Ion::LED::setLockState(bool state) {
-  lockState = state;
-}
+}*/
 
 // Private Ion::Device::LED methods
 
@@ -66,9 +53,12 @@ namespace Device {
 
 void init() {
   initGPIO();
+  initTimer();
 }
 
 void shutdown() {
+  shutdownTimer();
+  shutdownGPIO();
 }
 
 void initGPIO() {
@@ -88,68 +78,7 @@ void shutdownGPIO() {
   }
 }
 
-void initTimer(Mode mode, float blinkPeriod) {
-  constexpr int TIM3_FREQ = 4*1000;
-
-  /* Pulse width modulation mode allows you to generate a signal with a
-   * frequency determined by the value of the TIMx_ARR register and a duty cycle
-   * determined by the value of the TIMx_CCRx register. */
-  switch (mode) {
-    case Ion::LED::Device::Mode::PWM:
-      /* Let's set the prescaler to 1. Increasing the prescaler would slow down the
-      * modulation, which can be useful when debugging. */
-      TIM3.PSC()->set(1);
-      TIM3.ARR()->set(PWMPeriod);
-      TIM3.CCR2()->set(0);
-      TIM3.CCR3()->set(0);
-      TIM3.CCR4()->set(0);
-      break;
-    case Ion::LED::Device::Mode::BLINK:
-      /* We still want to do PWM, but at a rate slow enough to blink. */
-      TIM3.PSC()->set(Ion::Device::SYSBUS_FREQ / TIM3_FREQ);
-      TIM3.ARR()->set(blinkPeriod * TIM3_FREQ);
-      TIM3.CCR2()->set(blinkPeriod * TIM3_FREQ / 2);
-      TIM3.CCR3()->set(blinkPeriod * TIM3_FREQ / 2);
-      TIM3.CCR4()->set(blinkPeriod * TIM3_FREQ / 2);
-      break;
-  }
-
-  // Set Channels 2-4 as outputs, PWM mode 1
-  TIM3.CCMR()->setOC2M(TIM<Register16>::CCMR::OCM::PWM1);
-  TIM3.CCMR()->setOC3M(TIM<Register16>::CCMR::OCM::PWM1);
-  TIM3.CCMR()->setOC4M(TIM<Register16>::CCMR::OCM::PWM1);
-
-  // Output preload enable for channels 2-4
-  TIM3.CCMR()->setOC2PE(true);
-  TIM3.CCMR()->setOC3PE(true);
-  TIM3.CCMR()->setOC4PE(true);
-
-  // Auto-reload preload enable
-  TIM3.CR1()->setARPE(true);
-
-  // Enable Capture/Compare for channel 2 to 4
-  TIM3.CCER()->setCC2E(true);
-  TIM3.CCER()->setCC3E(true);
-  TIM3.CCER()->setCC4E(true);
-
-  TIM3.BDTR()->setMOE(true);
-
-  TIM3.CR1()->setCEN(true);
-}
-
-void initTimerColor() {
-  /* Let's set the prescaler to 1. Increasing the prescaler would slow down the
-   * modulation, which can be useful when debugging. */
-  TIM3.PSC()->set(1);
-
-  /* Pulse width modulation mode allows you to generate a signal with a
-   * frequency determined by the value of the TIMx_ARR register and a duty cycle
-   * determined by the value of the TIMx_CCRx register. */
-  TIM3.ARR()->set(PWMPeriod);
-  TIM3.CCR2()->set(0);
-  TIM3.CCR3()->set(0);
-  TIM3.CCR4()->set(0);
-
+void initTimer() {
   // Output preload enable for channels 2-4
   TIM3.CCMR()->setOC2PE(true);
   TIM3.CCMR()->setOC3PE(true);
@@ -174,6 +103,33 @@ void shutdownTimer() {
   setColorStatus(Ion::LED::Device::Color::BLUE, false);
 }
 
+/* Pulse width modulation mode allows you to generate a signal with a
+ * frequency determined by the value of the TIMx_ARR register and a duty cycle
+ * determined by the value of the TIMx_CCRx register. */
+
+void setPeriodAndDutyCycles(Mode mode, float dutyCycleRed, float dutyCycleGreen, float dutyCycleBlue, float period) {
+  constexpr int TIM3_FREQ = 4*1000;
+  switch (mode) {
+    case Mode::PWM:
+      /* Let's set the prescaler to 1. Increasing the prescaler would slow down the
+       * modulation, which can be useful when debugging. */
+      TIM3.PSC()->set(1);
+      TIM3.ARR()->set(PWMPeriod);
+      period = PWMPeriod;
+      break;
+    case Mode::BLINK:
+      /* We still want to do PWM, but at a rate slow enough to blink. */
+      TIM3.PSC()->set(Ion::Device::SYSBUS_FREQ / TIM3_FREQ);
+      TIM3.ARR()->set(period * TIM3_FREQ);
+      period *= TIM3_FREQ; // as we pre-scaled, we update the period
+      break;
+  }
+
+  TIM3.CCR2()->set(dutyCycleRed*period);
+  TIM3.CCR3()->set(dutyCycleBlue*period);
+  TIM3.CCR4()->set(dutyCycleGreen*period);
+}
+
 void setColorStatus(Color color, bool enable) {
   switch (color) {
     case Ion::LED::Device::Color::RED:
@@ -188,7 +144,7 @@ void setColorStatus(Color color, bool enable) {
   }
 }
 
-void enforceState(bool red, bool green, bool blue) {
+/*void enforceState(bool red, bool green, bool blue) {
   bool states[3] = {red, green, blue};
   for (int i=0; i<3; i++) {
     GPIOPin p = RGBPins[i];
@@ -200,7 +156,7 @@ void enforceState(bool red, bool green, bool blue) {
       p.group().PUPDR()->setPull(p.pin(), GPIO::PUPDR::Pull::None);
     }
   }
-}
+}*/
 
 }
 }
diff --git a/ion/src/device/led.h b/ion/src/device/led.h
index 19a918366..426ce9607 100644
--- a/ion/src/device/led.h
+++ b/ion/src/device/led.h
@@ -17,23 +17,24 @@ namespace Device {
 enum Mode {
   PWM,
   BLINK
-} ;
+};
 
 enum Color {
   RED,
   GREEN,
   BLUE
-} ;
+};
 
 void init();
 void shutdown();
+void setPeriodAndDutyCycles(Mode mode, float dutyCycleRed, float dutyCycleGreen, float dutyCycleBlue, float period = 0.0f);
 void setColorStatus(Color color, bool enable);
 /* This call bypasses the timer, and immediately enforces a given LED state. */
-void enforceState(bool red, bool green, bool blue);
+//void enforceState(bool red, bool green, bool blue);
 
 void initGPIO();
 void shutdownGPIO();
-void initTimer(Mode mode, float blinkPeriod = 0);
+void initTimer();
 void shutdownTimer();
 
 constexpr static GPIOPin RGBPins[] = {
@@ -43,11 +44,6 @@ constexpr static GPIOPin RGBPins[] = {
 
 constexpr uint16_t PWMPeriod = 40000;
 
-inline uint16_t dutyCycleForUInt8(uint8_t value) {
-  /* This function is a linear function from colors [0->255] to duty cycles [0->PWMPeriod].*/
-  return ((uint32_t)value)*(PWMPeriod/255);
-}
-
 }
 }
 }
diff --git a/ion/src/device/power.cpp b/ion/src/device/power.cpp
index 0d0cacf93..021d75cc6 100644
--- a/ion/src/device/power.cpp
+++ b/ion/src/device/power.cpp
@@ -9,6 +9,7 @@
 #include "regs/regs.h"
 
 void Ion::Power::suspend(bool checkIfPowerKeyReleased) {
+  bool isLEDActive = Ion::LED::getColor() != KDColorBlack;
   if (checkIfPowerKeyReleased) {
     /* Wait until power is released to avoid restarting just after suspending */
     bool isPowerDown = true;
@@ -17,11 +18,11 @@ void Ion::Power::suspend(bool checkIfPowerKeyReleased) {
       isPowerDown = scan.keyDown(Keyboard::Key::B2);
     }
   }
-  Device::shutdownPeripherals();
+  Device::shutdownPeripherals(isLEDActive);
 
   PWR.CR()->setLPDS(true); // Turn the regulator off. Takes longer to wake up.
   PWR.CR()->setFPDS(true); // Put the flash to sleep. Takes longer to wake up.
-  CM4.SCR()->setSLEEPDEEP(!Ion::LED::getLockState());
+  CM4.SCR()->setSLEEPDEEP(!isLEDActive);
 
   while (1) {
 #if EPSILON_LED_WHILE_CHARGING
@@ -29,7 +30,7 @@ void Ion::Power::suspend(bool checkIfPowerKeyReleased) {
      * if the standby mode was stopped due to a "stop charging" event, we wait
      * a while to be sure that the plug state of the USB is up-to-date. */
     msleep(200);
-    Ion::LED::setCharging(Ion::USB::isPlugged(), Ion::Battery::isCharging());
+    //Ion::LED::setCharging(Ion::USB::isPlugged(), Ion::Battery::isCharging());
 #endif
 
     WakeUp::Device::onPowerKeyDown();
@@ -38,7 +39,7 @@ void Ion::Power::suspend(bool checkIfPowerKeyReleased) {
     WakeUp::Device::onChargingEvent();
 #endif
 
-    Device::shutdownClocks();
+    Device::shutdownClocks(isLEDActive);
 
    /* To enter sleep, we need to issue a WFE instruction, which waits for the
    * event flag to be set and then clears it. However, the event flag might
diff --git a/ion/src/shared/dummy/led.cpp b/ion/src/shared/dummy/led.cpp
index 985b049a2..725c7c29d 100644
--- a/ion/src/shared/dummy/led.cpp
+++ b/ion/src/shared/dummy/led.cpp
@@ -1,17 +1,9 @@
 #include <ion/led.h>
 
-void Ion::LED::setColor(KDColor c) {
+KDColor getColor() {
+  return KDColorBlack;
 }
 
-void Ion::LED::setBlinking(float blinkPeriod, bool red, bool green, bool blue) {
-}
+void setColor(KDColor c) {}
 
-void Ion::LED::setCharging(bool isPlugged, bool isCharging) {
-}
-
-bool Ion::LED::getLockState() {
-  return false;
-}
-
-void Ion::LED::setLockState(bool state) {
-}
+void setBlinking(float period, float dutyCycle) {}
\ No newline at end of file
diff --git a/ion/src/simulator/Makefile b/ion/src/simulator/Makefile
index 9f73f59b1..9185e96b4 100644
--- a/ion/src/simulator/Makefile
+++ b/ion/src/simulator/Makefile
@@ -1,6 +1,5 @@
 objs += $(addprefix ion/src/simulator/, \
   init.o\
-  led.o\
 )
 
 objs += $(addprefix ion/src/simulator/boot/, main.o)
@@ -17,6 +16,7 @@ objs += $(addprefix ion/src/shared/, \
   dummy/backlight.o \
   dummy/battery.o \
   dummy/fcc_id.o \
+  dummy/led.o \
   dummy/serial_number.o \
   dummy/usb.o \
 )
diff --git a/ion/src/simulator/led.cpp b/ion/src/simulator/led.cpp
deleted file mode 100644
index 985b049a2..000000000
--- a/ion/src/simulator/led.cpp
+++ /dev/null
@@ -1,17 +0,0 @@
-#include <ion/led.h>
-
-void Ion::LED::setColor(KDColor c) {
-}
-
-void Ion::LED::setBlinking(float blinkPeriod, bool red, bool green, bool blue) {
-}
-
-void Ion::LED::setCharging(bool isPlugged, bool isCharging) {
-}
-
-bool Ion::LED::getLockState() {
-  return false;
-}
-
-void Ion::LED::setLockState(bool state) {
-}