diff --git a/babblesim/hw/bsp/nrf52_bsim/syscfg.yml b/babblesim/hw/bsp/nrf52_bsim/syscfg.yml
index c73106f32..e5733dd52 100644
--- a/babblesim/hw/bsp/nrf52_bsim/syscfg.yml
+++ b/babblesim/hw/bsp/nrf52_bsim/syscfg.yml
@@ -17,6 +17,7 @@
 #
 
 syscfg.defs:
+    BABBLESIM: 1
     BSP_NRF52:
         description: 'Set to indicate that BSP has NRF52'
         value: 1