diff --git a/target/linux/bcm53xx/image/Makefile b/target/linux/bcm53xx/image/Makefile
index 41281f9066..04e418d1e9 100644
--- a/target/linux/bcm53xx/image/Makefile
+++ b/target/linux/bcm53xx/image/Makefile
@@ -37,6 +37,7 @@ endef
 define Build/trx-serial
 	$(STAGING_DIR_HOST)/bin/trx \
 		-o $@ \
+		-m 33554432 \
 		-f $(word 1,$^) -a 1024 \
 		-f $(KDIR)/root.squashfs -a 0x10000 -A $(KDIR)/fs_mark
 endef