diff --git a/ports/stm/boards/STM32F401xd_fs.ld b/ports/stm/boards/STM32F401xd_fs.ld
index 3086c2c6b0..69bae46cb6 100644
--- a/ports/stm/boards/STM32F401xd_fs.ld
+++ b/ports/stm/boards/STM32F401xd_fs.ld
@@ -13,7 +13,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F401xe_boot.ld b/ports/stm/boards/STM32F401xe_boot.ld
index 0409476949..37827c3301 100644
--- a/ports/stm/boards/STM32F401xe_boot.ld
+++ b/ports/stm/boards/STM32F401xe_boot.ld
@@ -12,7 +12,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F401xe_fs.ld b/ports/stm/boards/STM32F401xe_fs.ld
index b55bc4bb4a..20247930c2 100644
--- a/ports/stm/boards/STM32F401xe_fs.ld
+++ b/ports/stm/boards/STM32F401xe_fs.ld
@@ -13,7 +13,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F405_boot.ld b/ports/stm/boards/STM32F405_boot.ld
index 906f56e0d2..5768d1a01e 100644
--- a/ports/stm/boards/STM32F405_boot.ld
+++ b/ports/stm/boards/STM32F405_boot.ld
@@ -13,7 +13,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define the top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F405_default.ld b/ports/stm/boards/STM32F405_default.ld
index 0aafdbcac5..4c11fd7cf3 100644
--- a/ports/stm/boards/STM32F405_default.ld
+++ b/ports/stm/boards/STM32F405_default.ld
@@ -13,7 +13,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F405_fs.ld b/ports/stm/boards/STM32F405_fs.ld
index bff312660e..e6c66127fb 100644
--- a/ports/stm/boards/STM32F405_fs.ld
+++ b/ports/stm/boards/STM32F405_fs.ld
@@ -14,7 +14,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F407_fs.ld b/ports/stm/boards/STM32F407_fs.ld
index 5330b4116f..f06c19d992 100644
--- a/ports/stm/boards/STM32F407_fs.ld
+++ b/ports/stm/boards/STM32F407_fs.ld
@@ -14,7 +14,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F411_fs.ld b/ports/stm/boards/STM32F411_fs.ld
index 82c7aea065..1b45f235fa 100644
--- a/ports/stm/boards/STM32F411_fs.ld
+++ b/ports/stm/boards/STM32F411_fs.ld
@@ -13,7 +13,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F411_nvm.ld b/ports/stm/boards/STM32F411_nvm.ld
index 897b996313..5ac3e52a6e 100644
--- a/ports/stm/boards/STM32F411_nvm.ld
+++ b/ports/stm/boards/STM32F411_nvm.ld
@@ -14,7 +14,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define the top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F412_fs.ld b/ports/stm/boards/STM32F412_fs.ld
index afd51c6b19..8837bd87d6 100644
--- a/ports/stm/boards/STM32F412_fs.ld
+++ b/ports/stm/boards/STM32F412_fs.ld
@@ -13,7 +13,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F746xG_fs.ld b/ports/stm/boards/STM32F746xG_fs.ld
index f1bd3d5dc0..be10a14294 100644
--- a/ports/stm/boards/STM32F746xG_fs.ld
+++ b/ports/stm/boards/STM32F746xG_fs.ld
@@ -38,7 +38,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32F767_fs.ld b/ports/stm/boards/STM32F767_fs.ld
index 40e67829bf..25322b0b6f 100644
--- a/ports/stm/boards/STM32F767_fs.ld
+++ b/ports/stm/boards/STM32F767_fs.ld
@@ -13,7 +13,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K;
 _minimum_heap_size = 16K;
 
 /* Define tho top end of the stack.  The stack is full descending so begins just
diff --git a/ports/stm/boards/STM32H743_fs.ld b/ports/stm/boards/STM32H743_fs.ld
index 686f93ea36..b6c3d5b62d 100644
--- a/ports/stm/boards/STM32H743_fs.ld
+++ b/ports/stm/boards/STM32H743_fs.ld
@@ -22,7 +22,7 @@ MEMORY
 }
 
 /* produce a link error if there is not this amount of RAM for these sections */
-_minimum_stack_size = 2K;
+_minimum_stack_size = 24K; /*TODO: this can probably be bigger, but how big?*/
 _minimum_heap_size = 16K;
 
 /* brainless copy paste for stack code. Results in ambiguous hard crash */
diff --git a/ports/stm/supervisor/port.c b/ports/stm/supervisor/port.c
index 328a8d660c..23ba7d8745 100644
--- a/ports/stm/supervisor/port.c
+++ b/ports/stm/supervisor/port.c
@@ -49,7 +49,7 @@
 #include STM32_HAL_H
 
 //only enable the Reset Handler overwrite for the H7 for now
-#if defined(STM32H7)
+#if (CPY_STM32H7)
 
 // Device memories must be accessed in order.
 #define DEVICE 2
@@ -162,7 +162,7 @@ safe_mode_t port_init(void) {
     HAL_Init();
     __HAL_RCC_SYSCFG_CLK_ENABLE();
 
-    #if defined(STM32F4)
+    #if (CPY_STM32F4)
         __HAL_RCC_PWR_CLK_ENABLE();
     #endif
 
@@ -170,31 +170,63 @@ safe_mode_t port_init(void) {
     stm32_peripherals_gpio_init();
 
     HAL_PWR_EnableBkUpAccess();
+
+    // TODO: move all of this to clocks.c
     #if BOARD_HAS_LOW_SPEED_CRYSTAL
-    __HAL_RCC_LSE_CONFIG(RCC_LSE_ON);
+    uint32_t tickstart = HAL_GetTick();
+
+    // H7/F7 untested with LSE, so autofail them until above move is done
+    #if (CPY_STM32F4) 
     bool lse_setupsuccess = true;
-    uint32_t i = 0;
+    #else
+    bool lse_setupsuccess = false;
+    #endif
+
+    // Update LSE configuration in Backup Domain control register
+    // Requires to enable write access to Backup Domain of necessary
+    // TODO: should be using the HAL OSC initializer, otherwise we'll need
+    // preprocessor defines for every register to account for F7/H7
+    #if (CPY_STM32F4)
+    if(HAL_IS_BIT_CLR(PWR->CR, PWR_CR_DBP))
+    {
+        // Enable write access to Backup domain
+        SET_BIT(PWR->CR, PWR_CR_DBP);
+        // Wait for Backup domain Write protection disable
+        tickstart = HAL_GetTick();
+        while(HAL_IS_BIT_CLR(PWR->CR, PWR_CR_DBP))
+        {
+            if((HAL_GetTick() - tickstart) > RCC_DBP_TIMEOUT_VALUE)
+            {
+                lse_setupsuccess = false;
+            }
+        }
+    }
+    #endif
+
+    __HAL_RCC_LSE_CONFIG(RCC_LSE_ON);
+    tickstart = HAL_GetTick();
     while(__HAL_RCC_GET_FLAG(RCC_FLAG_LSERDY) == RESET) {
-        if ( ++i > 1000000 )
+        if((HAL_GetTick() - tickstart ) > LSE_STARTUP_TIMEOUT)
         {
             lse_setupsuccess = false;
             __HAL_RCC_LSE_CONFIG(RCC_LSE_OFF);
             __HAL_RCC_LSI_ENABLE();
             rtc_clock_frequency = LSI_VALUE;
+            break;
         }
     }
-    #else
-    __HAL_RCC_LSI_ENABLE();
-    #endif
-    #if BOARD_HAS_LOW_SPEED_CRYSTAL
+
     if (lse_setupsuccess) {
         __HAL_RCC_RTC_CONFIG(RCC_RTCCLKSOURCE_LSE);
     } else {
         __HAL_RCC_RTC_CONFIG(RCC_RTCCLKSOURCE_LSI);
     }
+
     #else
+    __HAL_RCC_LSI_ENABLE();
     __HAL_RCC_RTC_CONFIG(RCC_RTCCLKSOURCE_LSI);
     #endif
+
     __HAL_RCC_RTC_ENABLE();
     _hrtc.Instance = RTC;
     _hrtc.Init.HourFormat = RTC_HOURFORMAT_24;