Turn off HSI earlier

src/main.c

@@ -17,6 +17,9 @@ static void system_clock_init(void) {
   PWR->CR &= ~(PWR_CR_VOS_MASK << PWR_CR_VOS_BIT);
   PWR->CR |= (PWR_SCALE3 << PWR_CR_VOS_BIT);
 
+  // Turn off HSI (which is on by default)
+  RCC->CR &= ~RCC_CR_HSION_ON;
+
   // Turn on HSE
   RCC->CR |= RCC_CR_HSEON_ON;
 
@@ -68,9 +71,6 @@ static void system_clock_init(void) {
   // Wait indefinitely for PLL clock to be selected
   // TODO indicate error/timeout somehow?
   while (((RCC->CFGR >> RCC_CFGR_SWS_BIT) & RCC_CFGR_SWS_MASK) != RCC_CFGR_SWS_PLL);
-
-  // Turn off HSI (which is on by default)
-  RCC->CR &= ~RCC_CR_HSION_ON;
 }
 
 int main(void) {