diff --git a/arch/ARM/STM32/drivers/stm32-timers.adb b/arch/ARM/STM32/drivers/stm32-timers.adb
index 9d58cd4b7..b4536c170 100644
--- a/arch/ARM/STM32/drivers/stm32-timers.adb
+++ b/arch/ARM/STM32/drivers/stm32-timers.adb
@@ -184,6 +184,10 @@ package body STM32.Timers is
    procedure Enable_Main_Output (This : in out Timer) is
    begin
       This.BDTR.Main_Output_Enabled := True;
+
+      loop
+         exit when Main_Output_Enabled (This);
+      end loop;
    end Enable_Main_Output;
 
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