diff --git a/ports/stm32/mboot/Makefile b/ports/stm32/mboot/Makefile
index 553fc4ac667f..7e1b497cef63 100755
--- a/ports/stm32/mboot/Makefile
+++ b/ports/stm32/mboot/Makefile
@@ -161,6 +161,7 @@ SRC_HAL += $(addprefix $(HAL_DIR)/Src/stm32$(MCU_SERIES)xx_,\
 	hal_flash_ex.c \
 	hal_pcd.c \
 	hal_pcd_ex.c \
+	hal_rcc.c \
 	ll_usb.c \
 	)
 
diff --git a/ports/stm32/mboot/main.c b/ports/stm32/mboot/main.c
index 278c07fb4a9d..3c3e4a8642a9 100644
--- a/ports/stm32/mboot/main.c
+++ b/ports/stm32/mboot/main.c
@@ -326,11 +326,6 @@ void SystemClock_Config(void) {
 
 #endif
 
-// Needed by HAL_PCD_IRQHandler
-uint32_t HAL_RCC_GetHCLKFreq(void) {
-    return SystemCoreClock;
-}
-
 /******************************************************************************/
 // GPIO