diff --git a/src/main/drivers/at32/timer_at32bsp.c b/src/main/drivers/at32/timer_at32bsp.c
index d14c39e31c..0f059a9b23 100644
--- a/src/main/drivers/at32/timer_at32bsp.c
+++ b/src/main/drivers/at32/timer_at32bsp.c
@@ -696,11 +696,9 @@ void timerInit(void)
     }
 }
 
-// finish configuring timers after allocation phase
-// start timers
-void timerStart(void)
+void timerStart(tmr_type *tim)
 {
-
+    tmr_counter_enable(tim, TRUE);
 }
 
 /**
diff --git a/src/main/drivers/serial_escserial.c b/src/main/drivers/serial_escserial.c
index d6f2d82307..3e53ffc186 100644
--- a/src/main/drivers/serial_escserial.c
+++ b/src/main/drivers/serial_escserial.c
@@ -111,7 +111,7 @@ typedef struct {
 
 escOutputs_t escOutputs[MAX_SUPPORTED_MOTORS];
 
-extern timerHardware_t* serialTimerHardware;
+//extern timerHardware_t* serialTimerHardware;
 
 const struct serialPortVTable escSerialVTable[];
 
@@ -135,11 +135,10 @@ enum {
 #define STOP_BIT_MASK (1 << 0)
 #define START_BIT_MASK (1 << (RX_TOTAL_BITS - 1))
 
-// XXX No TIM_DeInit equivalent in HAL driver???
 #ifdef USE_HAL_DRIVER
 static void TIM_DeInit(TIM_TypeDef *tim)
 {
-    UNUSED(tim);
+    LL_TIM_DeInit(tim);
 }
 #endif
 
@@ -183,7 +182,7 @@ static void escSerialGPIOConfig(const timerHardware_t *timhw, ioConfig_t cfg)
     }
 
     IOInit(IOGetByTag(tag), OWNER_MOTOR, 0);
-#ifdef STM32F7
+#if defined(STM32F7) || defined(STM32H7)
     IOConfigGPIOAF(IOGetByTag(tag), cfg, timhw->alternateFunction);
 #else
     IOConfigGPIO(IOGetByTag(tag), cfg);
@@ -194,7 +193,7 @@ static void escSerialInputPortConfig(const timerHardware_t *timerHardwarePtr)
 {
     escSerialGPIOConfig(timerHardwarePtr, IOCFG_AF_PP_UP);
     timerChClearCCFlag(timerHardwarePtr);
-    timerChITConfig(timerHardwarePtr,ENABLE);
+    timerChITConfig(timerHardwarePtr, ENABLE);
 }
 
 static bool isTimerPeriodTooLarge(uint32_t timerPeriod)
@@ -211,7 +210,7 @@ static bool isEscSerialTransmitBufferEmpty(const serialPort_t *instance)
 static void escSerialOutputPortConfig(const timerHardware_t *timerHardwarePtr)
 {
     escSerialGPIOConfig(timerHardwarePtr, IOCFG_OUT_PP);
-    timerChITConfig(timerHardwarePtr,DISABLE);
+    timerChITConfig(timerHardwarePtr, DISABLE);
 }
 
 static void processTxStateBL(escSerial_t *escSerial)
@@ -346,7 +345,7 @@ static void onSerialTimerBL(timerCCHandlerRec_t *cbRec, captureCompare_t capture
     processRxStateBL(escSerial);
 }
 
-static void serialTimerTxConfigBL(const timerHardware_t *timerHardwarePtr, uint8_t reference, uint32_t baud)
+static void serialTimerTxConfigBL(const timerHardware_t *timerHardwarePtr, uint8_t portIndex, uint32_t baud)
 {
     uint32_t clock = SystemCoreClock/2;
     uint32_t timerPeriod;
@@ -363,9 +362,10 @@ static void serialTimerTxConfigBL(const timerHardware_t *timerHardwarePtr, uint8
         }
     } while (isTimerPeriodTooLarge(timerPeriod));
 
-    timerConfigure(timerHardwarePtr, timerPeriod, clock);
-    timerChCCHandlerInit(&escSerialPorts[reference].timerCb, onSerialTimerBL);
-    timerChConfigCallbacks(timerHardwarePtr, &escSerialPorts[reference].timerCb, NULL);
+    timerReconfigureTimeBase(timerHardwarePtr->tim, timerPeriod, clock);
+    timerChCCHandlerInit(&escSerialPorts[portIndex].timerCb, onSerialTimerBL);
+    timerChConfigCallbacks(timerHardwarePtr, &escSerialPorts[portIndex].timerCb, NULL);
+    timerStart(timerHardwarePtr->tim);
 }
 
 static void onSerialRxPinChangeBL(timerCCHandlerRec_t *cbRec, captureCompare_t capture)
@@ -421,10 +421,11 @@ static void serialTimerRxConfigBL(const timerHardware_t *timerHardwarePtr, uint8
 {
     // start bit is usually a FALLING signal
     TIM_DeInit(timerHardwarePtr->tim);
-    timerConfigure(timerHardwarePtr, 0xFFFF, SystemCoreClock / 2);
+    timerReconfigureTimeBase(timerHardwarePtr->tim, 0xFFFF, SystemCoreClock / 2);
     timerChConfigIC(timerHardwarePtr, (options & SERIAL_INVERTED) ? ICPOLARITY_RISING : ICPOLARITY_FALLING, 0);
     timerChCCHandlerInit(&escSerialPorts[reference].edgeCb, onSerialRxPinChangeBL);
     timerChConfigCallbacks(timerHardwarePtr, &escSerialPorts[reference].edgeCb, NULL);
+    timerStart(timerHardwarePtr->tim);
 }
 
 #ifdef USE_ESCSERIAL_SIMONK
@@ -545,9 +546,10 @@ static void escSerialTimerTxConfig(const timerHardware_t *timerHardwarePtr, uint
 {
     uint32_t timerPeriod = 34;
     TIM_DeInit(timerHardwarePtr->tim);
-    timerConfigure(timerHardwarePtr, timerPeriod, MHZ_TO_HZ(1));
+    timerReconfigureTimeBase(timerHardwarePtr->tim, timerPeriod, MHZ_TO_HZ(1));
     timerChCCHandlerInit(&escSerialPorts[reference].timerCb, onSerialTimerEsc);
     timerChConfigCallbacks(timerHardwarePtr, &escSerialPorts[reference].timerCb, NULL);
+    timerStart(timerHardwarePtr->tim);
 }
 
 static void extractAndStoreRxByteEsc(escSerial_t *escSerial)
@@ -634,10 +636,11 @@ static void escSerialTimerRxConfig(const timerHardware_t *timerHardwarePtr, uint
 {
     // start bit is usually a FALLING signal
     TIM_DeInit(timerHardwarePtr->tim);
-    timerConfigure(timerHardwarePtr, 0xFFFF, MHZ_TO_HZ(1));
+    timerReconfigureTimeBase(timerHardwarePtr->tim, 0xFFFF, MHZ_TO_HZ(1));
     timerChConfigIC(timerHardwarePtr, ICPOLARITY_FALLING, 0);
     timerChCCHandlerInit(&escSerialPorts[reference].edgeCb, onSerialRxPinChangeEsc);
     timerChConfigCallbacks(timerHardwarePtr, &escSerialPorts[reference].edgeCb, NULL);
+    timerStart(timerHardwarePtr->tim);
 }
 #endif
 
@@ -678,6 +681,9 @@ static serialPort_t *openEscSerial(const motorDevConfig_t *motorConfig, escSeria
 #ifdef USE_HAL_DRIVER
         escSerial->rxTimerHandle = timerFindTimerHandle(escSerial->rxTimerHardware->tim);
 #endif
+        // Workaround to ensure that the timerHandle is configured before use, timer will be reconfigured to a different frequency below
+        // this prevents a null-pointer dereference in __HAL_TIM_CLEAR_FLAG called by timerChClearCCFlag and similar accesses of timerHandle without the Instance being configured first.
+        timerConfigure(escSerial->rxTimerHardware, 0xffff, 1);
     }
 
     escSerial->mode = mode;
@@ -690,6 +696,10 @@ static serialPort_t *openEscSerial(const motorDevConfig_t *motorConfig, escSeria
     escSerial->txTimerHandle = timerFindTimerHandle(escSerial->txTimerHardware->tim);
 #endif
 
+    // Workaround to ensure that the timerHandle is configured before use, timer will be reconfigured to a different frequency below
+    // this prevents a null-pointer dereference in __HAL_TIM_CLEAR_FLAG called by timerChClearCCFlag and similar accesses of timerHandle without the Instance being configured first.
+    timerConfigure(escSerial->txTimerHardware, 0xffff, 1);
+
     escSerial->port.vTable = escSerialVTable;
     escSerial->port.baudRate = baud;
     escSerial->port.mode = MODE_RXTX;
@@ -941,9 +951,7 @@ bool escEnablePassthrough(serialPort_t *escPassthroughPort, const motorDevConfig
     uint8_t motor_output = escIndex;
     LED0_OFF;
     LED1_OFF;
-    //StopPwmAllMotors();
-    // XXX Review effect of motor refactor
-    //pwmDisableMotors();
+
     motorDisable();
     passPort = escPassthroughPort;
 
diff --git a/src/main/drivers/stm32/timer_hal.c b/src/main/drivers/stm32/timer_hal.c
index 25cafafb49..f3862a6f3f 100644
--- a/src/main/drivers/stm32/timer_hal.c
+++ b/src/main/drivers/stm32/timer_hal.c
@@ -773,16 +773,24 @@ static void timCCxHandler(TIM_TypeDef *tim, timerConfig_t *timerConfig)
             break;
         }
         case __builtin_clz(TIM_IT_CC1):
-            timerConfig->edgeCallback[0]->fn(timerConfig->edgeCallback[0], tim->CCR1);
+            if (timerConfig->edgeCallback[0]) {
+                timerConfig->edgeCallback[0]->fn(timerConfig->edgeCallback[0], tim->CCR1);
+            }
             break;
         case __builtin_clz(TIM_IT_CC2):
-            timerConfig->edgeCallback[1]->fn(timerConfig->edgeCallback[1], tim->CCR2);
+            if (timerConfig->edgeCallback[1]) {
+                timerConfig->edgeCallback[1]->fn(timerConfig->edgeCallback[1], tim->CCR2);
+            }
             break;
         case __builtin_clz(TIM_IT_CC3):
-            timerConfig->edgeCallback[2]->fn(timerConfig->edgeCallback[2], tim->CCR3);
+            if (timerConfig->edgeCallback[2]) {
+                timerConfig->edgeCallback[2]->fn(timerConfig->edgeCallback[2], tim->CCR3);
+            }
             break;
         case __builtin_clz(TIM_IT_CC4):
-            timerConfig->edgeCallback[3]->fn(timerConfig->edgeCallback[3], tim->CCR4);
+            if (timerConfig->edgeCallback[3]) {
+                timerConfig->edgeCallback[3]->fn(timerConfig->edgeCallback[3], tim->CCR4);
+            }
             break;
         }
     }
@@ -1043,35 +1051,12 @@ void timerInit(void)
     }
 }
 
-// finish configuring timers after allocation phase
-// start timers
-// TODO - Work in progress - initialization routine must be modified/verified to start correctly without timers
-void timerStart(void)
+void timerStart(TIM_TypeDef *tim)
 {
-#if 0
-    for (unsigned timer = 0; timer < USED_TIMER_COUNT; timer++) {
-        int priority = -1;
-        int irq = -1;
-        for (unsigned hwc = 0; hwc < TIMER_CHANNEL_COUNT; hwc++) {
-            if ((timerChannelInfo[hwc].type != TYPE_FREE) && (TIMER_HARDWARE[hwc].tim == usedTimers[timer])) {
-                // TODO - move IRQ to timer info
-                irq = TIMER_HARDWARE[hwc].irq;
-            }
-        }
-        // TODO - aggregate required timer paramaters
-        configTimeBase(usedTimers[timer], 0, 1);
-        TIM_Cmd(usedTimers[timer], ENABLE);
-        if (priority >= 0) {  // maybe none of the channels was configured
-            NVIC_InitTypeDef NVIC_InitStructure;
+    TIM_HandleTypeDef* handle = timerFindTimerHandle(tim);
+    if (handle == NULL) return;
 
-            NVIC_InitStructure.NVIC_IRQChannel = irq;
-            NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = NVIC_SPLIT_PRIORITY_BASE(priority);
-            NVIC_InitStructure.NVIC_IRQChannelSubPriority = NVIC_SPLIT_PRIORITY_SUB(priority);
-            NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
-            NVIC_Init(&NVIC_InitStructure);
-        }
-    }
-#endif
+    __HAL_TIM_ENABLE(handle);
 }
 
 /**
diff --git a/src/main/drivers/stm32/timer_stdperiph.c b/src/main/drivers/stm32/timer_stdperiph.c
index ec0e008c2d..4b809c81aa 100644
--- a/src/main/drivers/stm32/timer_stdperiph.c
+++ b/src/main/drivers/stm32/timer_stdperiph.c
@@ -321,6 +321,11 @@ void timerNVICConfigure(uint8_t irq)
     NVIC_Init(&NVIC_InitStructure);
 }
 
+void timerReconfigureTimeBase(TIM_TypeDef *tim, uint16_t period, uint32_t hz)
+{
+    configTimeBase(tim, period, hz);
+}
+
 void configTimeBase(TIM_TypeDef *tim, uint16_t period, uint32_t hz)
 {
     TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
@@ -851,34 +856,9 @@ void timerInit(void)
     }
 }
 
-// finish configuring timers after allocation phase
-// start timers
-// TODO - Work in progress - initialization routine must be modified/verified to start correctly without timers
-void timerStart(void)
+void timerStart(TIM_TypeDef *tim)
 {
-#if 0
-    for (unsigned timer = 0; timer < USED_TIMER_COUNT; timer++) {
-        int priority = -1;
-        int irq = -1;
-        for (unsigned hwc = 0; hwc < TIMER_CHANNEL_COUNT; hwc++)
-            if ((timerChannelInfo[hwc].type != TYPE_FREE) && (TIMER_HARDWARE[hwc].tim == usedTimers[timer])) {
-                // TODO - move IRQ to timer info
-                irq = TIMER_HARDWARE[hwc].irq;
-            }
-        // TODO - aggregate required timer parameters
-        configTimeBase(usedTimers[timer], 0, 1);
-        TIM_Cmd(usedTimers[timer],  ENABLE);
-        if (priority >= 0) {  // maybe none of the channels was configured
-            NVIC_InitTypeDef NVIC_InitStructure;
-
-            NVIC_InitStructure.NVIC_IRQChannel = irq;
-            NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = NVIC_SPLIT_PRIORITY_BASE(priority);
-            NVIC_InitStructure.NVIC_IRQChannelSubPriority = NVIC_SPLIT_PRIORITY_SUB(priority);
-            NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
-            NVIC_Init(&NVIC_InitStructure);
-        }
-    }
-#endif
+    TIM_Cmd(tim,  ENABLE);
 }
 
 /**
diff --git a/src/main/drivers/timer.h b/src/main/drivers/timer.h
index c7231b83d8..9854aec4b8 100644
--- a/src/main/drivers/timer.h
+++ b/src/main/drivers/timer.h
@@ -134,7 +134,13 @@ void timerConfigure(const timerHardware_t *timHw, uint16_t period, uint32_t hz);
 // Initialisation
 //
 void timerInit(void);
-void timerStart(void);
+
+//
+// per-timer
+//
+
+// once-upon-a-time all the timers were started on boot, now they are started when needed.
+void timerStart(TIM_TypeDef *tim);
 
 //
 // per-channel
diff --git a/src/main/fc/init.c b/src/main/fc/init.c
index 14e0917e7e..cd055c638b 100644
--- a/src/main/fc/init.c
+++ b/src/main/fc/init.c
@@ -855,12 +855,6 @@ void init(void)
 
 #endif // VTX_CONTROL
 
-#ifdef USE_TIMER
-    // start all timers
-    // TODO - not implemented yet
-    timerStart();
-#endif
-
     batteryInit(); // always needs doing, regardless of features.
 
 #ifdef USE_RCDEVICE
diff --git a/src/main/target/SITL/sitl.c b/src/main/target/SITL/sitl.c
index 4302bf20aa..a89f3bdd2d 100644
--- a/src/main/target/SITL/sitl.c
+++ b/src/main/target/SITL/sitl.c
@@ -358,10 +358,6 @@ void timerInit(void)
     printf("[timer]Init...\n");
 }
 
-void timerStart(void)
-{
-}
-
 void failureMode(failureMode_e mode)
 {
     printf("[failureMode]!!! %d\n", mode);
diff --git a/src/main/target/STM32F7X2/target.h b/src/main/target/STM32F7X2/target.h
index 62930a6be8..a12432653a 100644
--- a/src/main/target/STM32F7X2/target.h
+++ b/src/main/target/STM32F7X2/target.h
@@ -70,10 +70,6 @@
 
 #define USE_USB_DETECT
 
-#ifdef USE_ESCSERIAL
-#undef USE_ESCSERIAL
-#endif
-
 #define USE_ADC
 #define USE_EXTI
 #define FLASH_PAGE_SIZE ((uint32_t)0x4000) // 16K sectors