diff --git a/chip/g/build.mk b/chip/g/build.mk
index 3564865f6b..11246a7fed 100644
--- a/chip/g/build.mk
+++ b/chip/g/build.mk
@@ -76,4 +76,5 @@ $(out)/RW/ec.RW.flat: $(out)/util/signer
 
 ifneq ($(CONFIG_RW_B),)
 $(out)/$(PROJECT).obj: $(out)/RW/ec.RW_B.flat
+$(out)/RW/ec.RW_B.flat: $(out)/util/signer
 endif