diff --git a/firmware/blinky/blinky.c b/firmware/blinky/blinky.c
index fdaf3ef7a..4bd111068 100644
--- a/firmware/blinky/blinky.c
+++ b/firmware/blinky/blinky.c
@@ -45,13 +45,13 @@ int main(void)
 		led_on(LED2);
 		led_on(LED3);
 
-		delay(2000000);
+		delay_ms(150);
 
 		led_off(LED1);
 		led_off(LED2);
 		led_off(LED3);
 
-		delay(2000000);
+		delay_ms(150);
 	}
 
 	return 0;
diff --git a/firmware/common/clock_gen.c b/firmware/common/clock_gen.c
index 22f461c2d..8a75074f8 100644
--- a/firmware/common/clock_gen.c
+++ b/firmware/common/clock_gen.c
@@ -148,7 +148,7 @@ clock_source_t activate_best_clock_source(void)
 			/* Enable PortaPack reference oscillator (if present), and check for valid clock. */
 			if (portapack_reference_oscillator && portapack()) {
 				portapack_reference_oscillator(true);
-				delay(510000); /* loop iterations @ 204MHz for >10ms for oscillator to enable. */
+				delay_ms(18); // for oscillator to enable.
 				if (si5351c_clkin_signal_valid(&si5351c)) {
 					source = CLOCK_SOURCE_PORTAPACK;
 				} else {
diff --git a/firmware/common/cpu_clock.c b/firmware/common/cpu_clock.c
index 325de76fd..32fd012c0 100644
--- a/firmware/common/cpu_clock.c
+++ b/firmware/common/cpu_clock.c
@@ -33,6 +33,9 @@
 #include "i2c_lpc.h"
 #include "si5351c.h"
 
+/* We start with the CPU clock at 96MHz */
+unsigned int cpu_clock_mhz = 96;
+
 /*
 Configure PLL1 (Main MCU Clock) to max speed (204MHz).
 Note: PLL1 clock is used by M4/M0 core, Peripheral, APB1.
@@ -51,11 +54,14 @@ static void cpu_clock_pll1_max_speed(void)
 	reg_val |= CGU_BASE_M4_CLK_CLK_SEL(CGU_SRC_IRC) | CGU_BASE_M4_CLK_AUTOBLOCK(1);
 	CGU_BASE_M4_CLK = reg_val;
 
+	/* CPU is now at 12MHz */
+	cpu_clock_mhz = 12;
+
 	/* 2. Enable the crystal oscillator. */
 	CGU_XTAL_OSC_CTRL &= ~CGU_XTAL_OSC_CTRL_ENABLE_MASK;
 
 	/* 3. Wait 250us. */
-	delay_us_at_mhz(250, 12);
+	delay_us(250);
 
 	/* 4. Set the AUTOBLOCK bit. */
 	CGU_PLL1_CTRL |= CGU_PLL1_CTRL_AUTOBLOCK(1);
@@ -95,11 +101,17 @@ static void cpu_clock_pll1_max_speed(void)
 	reg_val |= CGU_BASE_M4_CLK_CLK_SEL(CGU_SRC_PLL1);
 	CGU_BASE_M4_CLK = reg_val;
 
+	/* CPU is now at 102MHz */
+	cpu_clock_mhz = 102;
+
 	/* 9. Wait 50us. */
-	delay_us_at_mhz(50, 102);
+	delay_us(50);
 
 	/* 10. Set the PLL1 P-divider to direct output mode (DIRECT=1). */
 	CGU_PLL1_CTRL |= CGU_PLL1_CTRL_DIRECT_MASK;
+
+	/* CPU is now at 204MHz */
+	cpu_clock_mhz = 204;
 }
 
 /* clock startup for LPC4320 configure PLL1 to max speed (204MHz).
diff --git a/firmware/common/cpu_clock.h b/firmware/common/cpu_clock.h
index 92ad64412..049296435 100644
--- a/firmware/common/cpu_clock.h
+++ b/firmware/common/cpu_clock.h
@@ -27,6 +27,9 @@ extern "C" {
 
 void cpu_clock_init(void);
 
+// Current clock speed in MHz, updated on clock changes.
+extern unsigned int cpu_clock_mhz;
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/firmware/common/delay.c b/firmware/common/delay.c
index ceb7693e1..b74389b2b 100644
--- a/firmware/common/delay.c
+++ b/firmware/common/delay.c
@@ -21,16 +21,9 @@
 
 #include "delay.h"
 
-void delay(uint32_t duration)
-{
-	uint32_t i;
-
-	for (i = 0; i < duration; i++) {
-		__asm__("nop");
-	}
-}
+#include "cpu_clock.h"
 
-void delay_us_at_mhz(uint32_t us, uint32_t mhz)
+static void delay_us_at_mhz(uint32_t us, uint32_t mhz)
 {
 #if defined(LPC43XX_M4)
 	// The loop below takes 3 cycles per iteration.
@@ -52,3 +45,13 @@ void delay_us_at_mhz(uint32_t us, uint32_t mhz)
 	#error "No delay loop implementation"
 #endif
 }
+
+void delay_us(uint32_t us)
+{
+	delay_us_at_mhz(us, cpu_clock_mhz);
+}
+
+void delay_ms(uint32_t ms)
+{
+	delay_us_at_mhz(ms * 1000, cpu_clock_mhz);
+}
diff --git a/firmware/common/delay.h b/firmware/common/delay.h
index 870ba39e9..eed806bbd 100644
--- a/firmware/common/delay.h
+++ b/firmware/common/delay.h
@@ -27,8 +27,8 @@ extern "C" {
 
 #include <stdint.h>
 
-void delay(uint32_t duration);
-void delay_us_at_mhz(uint32_t us, uint32_t mhz);
+void delay_us(uint32_t us);
+void delay_ms(uint32_t ms);
 
 #ifdef __cplusplus
 }
diff --git a/firmware/common/fpga_selftest.c b/firmware/common/fpga_selftest.c
index 06f2e8eea..7170422c3 100644
--- a/firmware/common/fpga_selftest.c
+++ b/firmware/common/fpga_selftest.c
@@ -200,7 +200,7 @@ bool fpga_if_xcvr_selftest(void)
 
 	// Capture 1: 4 Msps, tone at 0.5 MHz, narrowband filter OFF
 	sample_rate_set(SR_FP_MHZ(4), true);
-	delay_us_at_mhz(1000, 204);
+	delay_ms(1);
 	if (rx_samples(num_samples, 2000000) == -1) {
 		timeout = true;
 	}
@@ -211,7 +211,7 @@ bool fpga_if_xcvr_selftest(void)
 
 	// Capture 2: 4 Msps, tone at 0.5 MHz, narrowband filter ON
 	narrowband_filter_set(1);
-	delay_us_at_mhz(1000, 204);
+	delay_ms(1);
 	if (rx_samples(num_samples, 2000000) == -1) {
 		timeout = true;
 	}
@@ -224,7 +224,7 @@ bool fpga_if_xcvr_selftest(void)
 	fpga_set_tx_nco_pstep(&fpga, 255);
 	sample_rate_set(SR_FP_MHZ(20), true);
 	narrowband_filter_set(0);
-	delay_us_at_mhz(1000, 204);
+	delay_ms(1);
 	if (rx_samples(num_samples, 2000000) == -1) {
 		timeout = true;
 	}
@@ -235,7 +235,7 @@ bool fpga_if_xcvr_selftest(void)
 
 	// Capture 4: 20 Msps, tone at 5 MHz, narrowband filter ON
 	narrowband_filter_set(1);
-	delay_us_at_mhz(1000, 204);
+	delay_ms(1);
 	if (rx_samples(num_samples, 2000000) == -1) {
 		timeout = true;
 	}
diff --git a/firmware/common/ice40_spi.c b/firmware/common/ice40_spi.c
index 2685092a4..880e0be29 100644
--- a/firmware/common/ice40_spi.c
+++ b/firmware/common/ice40_spi.c
@@ -112,14 +112,14 @@ bool ice40_spi_syscfg_program(
 	gpio_clear(drv->gpio_select);
 
 	// Wait a minimum of 200 ns.
-	delay_us_at_mhz(1, 204 / 4); // 250 ns.
+	delay_us(1);
 
 	// Release CRESET_B or drive CRESET_B = 1.
 	gpio_set(drv->gpio_creset);
 
 	// Wait a minimum of 1200 μs to clear internal configuration memory.
 	// Testing showed us that we need to wait longer. Let's wait 1800 μs.
-	delay_us_at_mhz(1800, 204);
+	delay_us(1800);
 
 	// Set SPI_SS = 1, Send 8 dummy clocks.
 	gpio_set(drv->gpio_select);
diff --git a/firmware/common/leds.c b/firmware/common/leds.c
index ab9b56fba..e1fd507b7 100644
--- a/firmware/common/leds.c
+++ b/firmware/common/leds.c
@@ -84,17 +84,17 @@ void set_leds(const uint8_t state)
 	}
 }
 
-void halt_and_flash(const uint32_t duration)
+void halt_and_flash(const uint32_t period_ms)
 {
 	/* blink LED1, LED2, and LED3 */
 	while (1) {
 		led_on(LED1);
 		led_on(LED2);
 		led_on(LED3);
-		delay(duration);
+		delay_ms(period_ms / 2);
 		led_off(LED1);
 		led_off(LED2);
 		led_off(LED3);
-		delay(duration);
+		delay_ms(period_ms / 2);
 	}
 }
diff --git a/firmware/common/operacake_sctimer.c b/firmware/common/operacake_sctimer.c
index 76453e57b..c5ec8a3b9 100644
--- a/firmware/common/operacake_sctimer.c
+++ b/firmware/common/operacake_sctimer.c
@@ -75,7 +75,7 @@ void operacake_sctimer_init(void)
 	// there are additional instructions that fill the time. If the duration of
 	// the actions from here to the first access to the SCTimer is changed, then
 	// this delay may need to be increased.
-	delay(8);
+	delay_us(1);
 
 	// Pin definitions for the HackRF
 	// U2CTRL0
diff --git a/firmware/common/platform_detect.c b/firmware/common/platform_detect.c
index 7c9fb53d9..475ad1e1f 100644
--- a/firmware/common/platform_detect.c
+++ b/firmware/common/platform_detect.c
@@ -194,11 +194,11 @@ void detect_hardware_platform(void)
 	/* activate internal pull-down */
 	scu_pinmux(P5_0, SCU_GPIO_PDN | SCU_CONF_FUNCTION0);
 	scu_pinmux(P6_10, SCU_GPIO_PDN | SCU_CONF_FUNCTION0);
-	delay_us_at_mhz(4, 96);
+	delay_us(4);
 	/* tri-state for a moment before testing input */
 	scu_pinmux(P5_0, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
 	scu_pinmux(P6_10, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
-	delay_us_at_mhz(4, 96);
+	delay_us(4);
 	/* if input rose quickly, there must be an external pull-up */
 	detected_resistors |= (gpio_read(&gpio2_9_on_P5_0)) ? P5_0_PUP : 0;
 	detected_resistors |= (gpio_read(&gpio3_6_on_P6_10)) ? P6_10_PUP : 0;
@@ -207,12 +207,12 @@ void detect_hardware_platform(void)
 	scu_pinmux(P5_0, SCU_GPIO_PUP | SCU_CONF_FUNCTION0);
 	scu_pinmux(P6_10, SCU_GPIO_PUP | SCU_CONF_FUNCTION0);
 	scu_pinmux(P6_5, SCU_GPIO_PUP | SCU_CONF_FUNCTION0);
-	delay_us_at_mhz(4, 96);
+	delay_us(4);
 	/* tri-state for a moment before testing input */
 	scu_pinmux(P5_0, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
 	scu_pinmux(P6_10, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
 	scu_pinmux(P6_5, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
-	delay_us_at_mhz(4, 96);
+	delay_us(4);
 	/* if input fell quickly, there must be an external pull-down */
 	detected_resistors |= (gpio_read(&gpio2_9_on_P5_0)) ? 0 : P5_0_PDN;
 	detected_resistors |= (gpio_read(&gpio3_6_on_P6_10)) ? 0 : P6_10_PDN;
@@ -221,37 +221,37 @@ void detect_hardware_platform(void)
 	switch (detected_resistors) {
 	case JAWBREAKER_RESISTORS:
 		if (!(supported_platform() & PLATFORM_JAWBREAKER)) {
-			halt_and_flash(3000000);
+			halt_and_flash(500);
 		}
 		platform = BOARD_ID_JAWBREAKER;
 		return;
 	case RAD1O_RESISTORS:
 		if (!(supported_platform() & PLATFORM_RAD1O)) {
-			halt_and_flash(3000000);
+			halt_and_flash(500);
 		}
 		platform = BOARD_ID_RAD1O;
 		return;
 	case HACKRF1_OG_RESISTORS:
 		if (!(supported_platform() & PLATFORM_HACKRF1_OG)) {
-			halt_and_flash(3000000);
+			halt_and_flash(500);
 		}
 		platform = BOARD_ID_HACKRF1_OG;
 		break;
 	case HACKRF1_R9_RESISTORS:
 		if (!(supported_platform() & PLATFORM_HACKRF1_R9)) {
-			halt_and_flash(3000000);
+			halt_and_flash(500);
 		}
 		platform = BOARD_ID_HACKRF1_R9;
 		break;
 	case PRALINE_RESISTORS:
 		if (!(supported_platform() & PLATFORM_PRALINE)) {
-			halt_and_flash(3000000);
+			halt_and_flash(500);
 		}
 		platform = BOARD_ID_PRALINE;
 		break;
 	default:
 		platform = BOARD_ID_UNRECOGNIZED;
-		halt_and_flash(1000000);
+		halt_and_flash(150);
 	}
 
 	uint32_t adc0_3 = check_pin_strap(3);
diff --git a/firmware/common/portapack.c b/firmware/common/portapack.c
index d3d848fcf..0c3cbce2e 100644
--- a/firmware/common/portapack.c
+++ b/firmware/common/portapack.c
@@ -31,12 +31,6 @@
 #include "platform_gpio.h"
 #include "platform_scu.h"
 
-static void portapack_sleep_milliseconds(const uint32_t milliseconds)
-{
-	/* NOTE: Naively assumes 204 MHz instruction cycle clock and five instructions per count */
-	delay(milliseconds * 40800);
-}
-
 typedef struct {
 	gpio_t gpio_dir;
 	gpio_t gpio_lcd_rdx;
@@ -244,7 +238,7 @@ static void portapack_lcd_sleep_out(void)
 	// "It will be necessary to wait 120msec after sending Sleep Out
 	// command (when in Sleep In Mode) before Sleep In command can be
 	// sent."
-	portapack_sleep_milliseconds(120);
+	delay_ms(120);
 }
 
 static void portapack_lcd_display_on(void)
@@ -310,11 +304,11 @@ static void portapack_lcd_wake(void)
 static void portapack_lcd_reset(void)
 {
 	portapack_lcd_reset_state(false);
-	portapack_sleep_milliseconds(1);
+	delay_ms(1);
 	portapack_lcd_reset_state(true);
-	portapack_sleep_milliseconds(10);
+	delay_ms(10);
 	portapack_lcd_reset_state(false);
-	portapack_sleep_milliseconds(120);
+	delay_ms(120);
 }
 
 static void portapack_lcd_init(void)
diff --git a/firmware/common/power.c b/firmware/common/power.c
index 1256e5953..70c8c0f18 100644
--- a/firmware/common/power.c
+++ b/firmware/common/power.c
@@ -132,7 +132,7 @@ static inline void enable_rf_power_praline(void)
 	gpio_clear(platform_gpio()->vaa_disable);
 
 	/* Let the voltage stabilize */
-	delay(1000000);
+	delay_ms(35);
 }
 
 static inline void disable_rf_power_praline(void)
@@ -147,7 +147,7 @@ static inline void enable_rf_power_rad1o(void)
 	gpio_set(platform_gpio()->vaa_enable);
 
 	/* Let the voltage stabilize */
-	delay(1000000);
+	delay_ms(35);
 }
 
 static inline void disable_rf_power_rad1o(void)
diff --git a/firmware/common/rad1o/display.c b/firmware/common/rad1o/display.c
index 91813aab9..c0c090b32 100644
--- a/firmware/common/rad1o/display.c
+++ b/firmware/common/rad1o/display.c
@@ -10,12 +10,6 @@
 #include "gpio_lpc.h"
 #include "delay.h"
 
-static void delayms(const uint32_t milliseconds)
-{
-	/* NOTE: Naively assumes 204 MHz instruction cycle clock and five instructions per count */
-	delay(milliseconds * 40800);
-}
-
 static struct gpio gpio_lcd_cs = GPIO(4, 12);    /* P9_0 */
 static struct gpio gpio_lcd_bl_en = GPIO(0, 8);  /* P1_1 */
 static struct gpio gpio_lcd_reset = GPIO(5, 17); /* P9_4 */
@@ -85,9 +79,9 @@ void rad1o_lcdInit(void)
 
 	// Reset the display
 	gpio_clear(&gpio_lcd_reset);
-	delayms(100);
+	delay_ms(100);
 	gpio_set(&gpio_lcd_reset);
-	delayms(100);
+	delay_ms(100);
 
 	select();
 
@@ -115,7 +109,7 @@ void rad1o_lcdInit(void)
 		  (1 << 12) | (0 << 13) | (0 << 14) | 0);
 
 	write(0, 0x01); /* most color displays need the pause */
-	delayms(10);
+	delay_ms(10);
 
 	size_t i = 0;
 	while (i < sizeof(initseq_d)) {
diff --git a/firmware/common/rffc5071.c b/firmware/common/rffc5071.c
index 2a1866d26..df25987c7 100644
--- a/firmware/common/rffc5071.c
+++ b/firmware/common/rffc5071.c
@@ -163,13 +163,13 @@ void rffc5071_lock_test(rffc5071_driver_t* const drv)
 		rffc5071_enable(drv);
 
 		// Wait 1ms.
-		delay_us_at_mhz(1000, 204);
+		delay_ms(1);
 
 		// Check for lock.
 		lock = rffc5071_check_lock(drv);
 
 		rffc5071_disable(drv);
-		delay_us_at_mhz(100, 204);
+		delay_us(100);
 
 		selftest.mixer_locks[i] = lock;
 	}
diff --git a/firmware/common/si5351c.c b/firmware/common/si5351c.c
index 77d777033..6672b3b01 100644
--- a/firmware/common/si5351c.c
+++ b/firmware/common/si5351c.c
@@ -224,7 +224,7 @@ void si5351c_reset_plls(si5351c_driver_t* const drv, si5351c_pll_mask_t mask)
 	set_PLLA_RST(drv, (mask & SI5351C_PLL_MASK_A) ? true : false);
 	set_PLLB_RST(drv, (mask & SI5351C_PLL_MASK_B) ? true : false);
 	si5351c_regs_commit(drv);
-	delay_us_at_mhz(2000, 204);
+	delay_ms(2);
 	si5351c_enable_clock_outputs(drv);
 }
 
diff --git a/firmware/hackrf_usb/hackrf_usb.c b/firmware/hackrf_usb/hackrf_usb.c
index 5d71fa80b..f9a4e40b8 100644
--- a/firmware/hackrf_usb/hackrf_usb.c
+++ b/firmware/hackrf_usb/hackrf_usb.c
@@ -433,7 +433,7 @@ int main(void)
 	if (board_id != BOARD_ID_RAD1O) {
 		clock_gen_shutdown();
 	}
-	delay_us_at_mhz(10000, 96);
+	delay_ms(10);
 	pins_setup();
 #ifdef IS_PRALINE
 	if (IS_PRALINE) {
@@ -491,7 +491,7 @@ int main(void)
 #ifdef IS_NOT_PRALINE
 	if (IS_NOT_PRALINE) {
 		if (!cpld_jtag_sram_load(&jtag_cpld)) {
-			halt_and_flash(6000000);
+			halt_and_flash(1000);
 		}
 	}
 #endif
@@ -503,7 +503,7 @@ int main(void)
 	#else
 		fpga_image_load(&fpga_loader, 0);
 	#endif
-		delay_us_at_mhz(100, 204);
+		delay_us(100);
 		fpga_spi_selftest();
 		fpga_sgpio_selftest();
 	}
diff --git a/firmware/hackrf_usb/usb_api_cpld.c b/firmware/hackrf_usb/usb_api_cpld.c
index 391b93667..38103c811 100644
--- a/firmware/hackrf_usb/usb_api_cpld.c
+++ b/firmware/hackrf_usb/usb_api_cpld.c
@@ -76,7 +76,7 @@ void cpld_update(void)
 		cpld_xsvf_buffer,
 		refill_cpld_buffer);
 	if (error == 0) {
-		halt_and_flash(6000000);
+		halt_and_flash(1000);
 	} else {
 		/* LED3 (Red) steady on error */
 		led_on(LED3);