diff --git a/firmware/application/portapack.cpp b/firmware/application/portapack.cpp
index 6a1e032f..dc60c687 100644
--- a/firmware/application/portapack.cpp
+++ b/firmware/application/portapack.cpp
@@ -157,6 +157,59 @@ Backlight* backlight() {
 		: static_cast<portapack::Backlight*>(&backlight_on_off);
 }
 
+static void configure_unused_mcu_peripherals(const bool enabled) {
+	/* Disabling these peripherals reduces "idle" (PortaPack at main
+	 * menu) current by 42mA.
+	 */
+
+	/* Some surprising peripherals in use by PortaPack firmware:
+	 *
+	 * RITIMER: M0 SysTick substitute (because M0 has no SysTick)
+	 * TIMER3: M0 cycle/PCLK counter
+	 */
+
+	const uint32_t clock_run_state = enabled ? 1 : 0;
+
+	LPC_CCU1->CLK_APB3_I2C1_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_APB3_DAC_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_APB3_CAN0_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_APB1_MOTOCON_PWM_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_APB1_CAN1_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_LCD_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_ETHERNET_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_USB0_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_EMC_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_SCT_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_USB1_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_EMCDIV_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_WWDT_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_USART0_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_UART1_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_SSP0_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_TIMER1_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_USART2_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_USART3_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_TIMER2_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_M4_QEI_CFG.RUN = clock_run_state;
+
+	LPC_CCU1->CLK_USB1_CFG.RUN = clock_run_state;
+	LPC_CCU1->CLK_SPI_CFG.RUN = clock_run_state;
+
+	LPC_CCU2->CLK_APB2_USART3_CFG.RUN = clock_run_state;
+	LPC_CCU2->CLK_APB2_USART2_CFG.RUN = clock_run_state;
+	LPC_CCU2->CLK_APB0_UART1_CFG.RUN = clock_run_state;
+	LPC_CCU2->CLK_APB0_USART0_CFG.RUN = clock_run_state;
+	LPC_CCU2->CLK_APB0_SSP0_CFG.RUN = clock_run_state;
+}
+
+static void disable_unused_mcu_peripheral_clocks() {
+	configure_unused_mcu_peripherals(false);
+}
+
+static void enable_unused_mcu_peripheral_clocks() {
+	configure_unused_mcu_peripherals(true);
+}
+
 static void shutdown_base() {
 	clock_manager.shutdown();
 
@@ -167,49 +220,11 @@ static void shutdown_base() {
 
 	systick_stop();
 
+	enable_unused_mcu_peripheral_clocks();
+
 	hackrf::one::reset();
 }
 
-static void turn_off_unused_mcu_peripherals() {
-	/* RITIMER: M0 SysTick substitute (because M0 has no SysTick)
-	 * TIMER3: M0 cycle/PCLK counter
-	 */
-
-	// Reclaim about 42mA when idle at top menu.
-	LPC_CCU1->CLK_APB3_I2C1_CFG.RUN = 0;
-	LPC_CCU1->CLK_APB3_DAC_CFG.RUN = 0;
-	LPC_CCU1->CLK_APB3_CAN0_CFG.RUN = 0;
-	LPC_CCU1->CLK_APB1_MOTOCON_PWM_CFG.RUN = 0;
-	LPC_CCU1->CLK_APB1_CAN1_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_LCD_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_ETHERNET_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_USB0_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_EMC_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_SCT_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_USB1_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_EMCDIV_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_WWDT_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_USART0_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_UART1_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_SSP0_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_TIMER1_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_USART2_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_USART3_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_TIMER2_CFG.RUN = 0;
-	LPC_CCU1->CLK_M4_QEI_CFG.RUN = 0;
-
-	LPC_CCU1->CLK_USB1_CFG.RUN = 0;
-	LPC_CCU1->CLK_SPI_CFG.RUN = 0;
-
-	LPC_CCU2->CLK_APB2_USART3_CFG.RUN = 0;
-	LPC_CCU2->CLK_APB2_USART2_CFG.RUN = 0;
-	LPC_CCU2->CLK_APB0_UART1_CFG.RUN = 0;
-	LPC_CCU2->CLK_APB0_USART0_CFG.RUN = 0;
-	LPC_CCU2->CLK_APB0_SSP0_CFG.RUN = 0;
-
-	LPC_CREG->CREG0 |= (1 << 5);	// Disable USB0 PHY
-}
-
 bool init() {
 	for(const auto& pin : pins) {
 		pin.init();
@@ -235,7 +250,9 @@ bool init() {
 		| (0U << 15)	// SDA: Enable input glitch filter
 		;
 
-	turn_off_unused_mcu_peripherals();
+	disable_unused_mcu_peripheral_clocks();
+
+	LPC_CREG->CREG0 |= (1 << 5);	// Disable USB0 PHY
 
 	power.init();