diff --git a/platform/drivers/tones/toneGenerator_MDxx380.c b/platform/drivers/tones/toneGenerator_MDxx380.c
index 3be8ab5c..35c1a7e0 100644
--- a/platform/drivers/tones/toneGenerator_MDxx380.c
+++ b/platform/drivers/tones/toneGenerator_MDxx380.c
@@ -101,7 +101,8 @@ void toneGen_init()
 
     /*
      * Timer configuration:
-     * - APB1 frequency = 42MHz, with 1:10 prescaler we have Ftick = 4.2MHz
+     * - APB1 frequency = 42MHz but timer run at twice of this frequency: with
+     * 1:20 prescaler we have Ftick = 4.2MHz
      * - ARR = 255 (8-bit PWM), gives an update rate of 16.406kHz
      * - Nominal update rate is 16.384kHz -> error = +22.25Hz
      */
@@ -109,7 +110,7 @@ void toneGen_init()
     __DSB();
 
     TIM3->ARR   = 0xFF;
-    TIM3->PSC   = 9;
+    TIM3->PSC   = 19;
     TIM3->CCMR1 = TIM_CCMR1_OC2M_2  /* CH2 in PWM mode 1, preload enabled */
                 | TIM_CCMR1_OC2M_1
                 | TIM_CCMR1_OC2PE;
diff --git a/platform/targets/MD-380/platform.c b/platform/targets/MD-380/platform.c
index 4ebb41ea..48ef48d0 100644
--- a/platform/targets/MD-380/platform.c
+++ b/platform/targets/MD-380/platform.c
@@ -46,8 +46,9 @@ void platform_init()
     adc1_init();
 
     /*
-     * Configure TIM8 for backlight PWM: Fpwm = 100kHz, 8 bit of resolution
-     * APB2 freq. is 84MHz, then: PSC = 327 to have Ftick = 256.097kHz
+     * Configure TIM8 for backlight PWM: Fpwm = 100kHz with 8 bit of resolution.
+     * APB2 freq. is 84MHz, but timer runs at twice this frequency.
+     * Then: PSC = 655 to have Ftick = 256.097kHz
      * With ARR = 256, Fpwm is 100kHz;
      * Backlight pin is connected to TIM8 CR1.
      */
@@ -55,7 +56,7 @@ void platform_init()
     __DSB();
 
     TIM8->ARR = 255;
-    TIM8->PSC = 327;
+    TIM8->PSC = 654;
     TIM8->CNT = 0;
     TIM8->CR1   |= TIM_CR1_ARPE;    /* LCD backlight is on PC6, TIM8-CH1 */
     TIM8->CCMR1 |= TIM_CCMR1_OC1M_2
diff --git a/platform/targets/MD-390/platform.c b/platform/targets/MD-390/platform.c
index 4ebb41ea..48ef48d0 100644
--- a/platform/targets/MD-390/platform.c
+++ b/platform/targets/MD-390/platform.c
@@ -46,8 +46,9 @@ void platform_init()
     adc1_init();
 
     /*
-     * Configure TIM8 for backlight PWM: Fpwm = 100kHz, 8 bit of resolution
-     * APB2 freq. is 84MHz, then: PSC = 327 to have Ftick = 256.097kHz
+     * Configure TIM8 for backlight PWM: Fpwm = 100kHz with 8 bit of resolution.
+     * APB2 freq. is 84MHz, but timer runs at twice this frequency.
+     * Then: PSC = 655 to have Ftick = 256.097kHz
      * With ARR = 256, Fpwm is 100kHz;
      * Backlight pin is connected to TIM8 CR1.
      */
@@ -55,7 +56,7 @@ void platform_init()
     __DSB();
 
     TIM8->ARR = 255;
-    TIM8->PSC = 327;
+    TIM8->PSC = 654;
     TIM8->CNT = 0;
     TIM8->CR1   |= TIM_CR1_ARPE;    /* LCD backlight is on PC6, TIM8-CH1 */
     TIM8->CCMR1 |= TIM_CCMR1_OC1M_2
diff --git a/platform/targets/MD-UV380/platform.c b/platform/targets/MD-UV380/platform.c
index 2b486b76..939f2de4 100644
--- a/platform/targets/MD-UV380/platform.c
+++ b/platform/targets/MD-UV380/platform.c
@@ -67,15 +67,16 @@ void platform_init()
 
     #ifdef ENABLE_BKLIGHT_DIMMING
     /*
-     * Configure TIM11 for backlight PWM: Fpwm = 256Hz, 8 bit of resolution
-     * APB2 freq. is 84MHz, then: PSC = 1281 to have Ftick = 65.52kHz
+     * Configure TIM11 for backlight PWM: Fpwm = 256Hz, 8 bit of resolution.
+     * APB2 freq. is 84MHz but timer runs at twice this frequency, then:
+     * PSC = 2564 to have Ftick = 65.52kHz
      * With ARR = 256, Fpwm is 256Hz;
      */
     RCC->APB2ENR |= RCC_APB2ENR_TIM11EN;
     __DSB();
 
     TIM11->ARR = 255;
-    TIM11->PSC = 1282;
+    TIM11->PSC = 2563;
     TIM11->CNT = 0;
     TIM11->CR1   |= TIM_CR1_ARPE;
     TIM11->CCMR1 |= TIM_CCMR1_OC1M_2