diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 3161f2322eb2..ba2f1525f4ee 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -166,7 +166,7 @@ config BCM_FLEXRM_MBOX
 	depends on ARCH_BCM_IPROC || COMPILE_TEST
 	depends on HAS_DMA
 	select GENERIC_MSI_IRQ_DOMAIN
-	default ARCH_BCM_IPROC
+	default m if ARCH_BCM_IPROC
 	help
 	  Mailbox implementation of the Broadcom FlexRM ring manager,
 	  which provides access to various offload engines on Broadcom