diff --git a/tcl/target/stm32lx_stlink.cfg b/tcl/target/stm32lx_stlink.cfg
index f9211d23d..ed9865d06 100644
--- a/tcl/target/stm32lx_stlink.cfg
+++ b/tcl/target/stm32lx_stlink.cfg
@@ -18,3 +18,18 @@ source [find target/stm32_stlink.cfg]
 
 set _FLASHNAME $_CHIPNAME.flash
 flash bank $_FLASHNAME stm32lx 0 0 0 0 $_TARGETNAME
+
+proc stm32l_enable_HSI {} {
+	# Enable HSI as clock source
+	echo "STM32L: Enabling HSI"
+
+	# Set HSION in RCC_CR
+	mww 0x40023800 0x00000101
+
+	# Set HSI as SYSCLK
+	mww 0x40023808 0x00000001
+}
+
+$_TARGETNAME configure -event reset-init {
+	stm32l_enable_HSI
+}