diff --git a/ports/stm32/main.c b/ports/stm32/main.c
index c8de2fd868..6df7374cce 100644
--- a/ports/stm32/main.c
+++ b/ports/stm32/main.c
@@ -662,6 +662,7 @@ soft_reset_exit:
     MICROPY_BOARD_END_SOFT_RESET(&state);
 
     gc_sweep_all();
+    mp_deinit();
 
     goto soft_reset;
 }