diff --git a/toolchain/toolchain-external/toolchain-external-custom/Config.in.options b/toolchain/toolchain-external/toolchain-external-custom/Config.in.options
index 665765a104..9680509a13 100644
--- a/toolchain/toolchain-external/toolchain-external-custom/Config.in.options
+++ b/toolchain/toolchain-external/toolchain-external-custom/Config.in.options
@@ -92,6 +92,9 @@ config BR2_TOOLCHAIN_EXTERNAL_GCC_OLD
 
 endchoice
 
+comment "GCC older than 4.8 is not tested by Buildroot. Use at your own risk."
+	depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
+
 choice
 	bool "External toolchain kernel headers series"
 	default BR2_TOOLCHAIN_EXTERNAL_HEADERS_REALLY_OLD
@@ -298,6 +301,9 @@ config BR2_TOOLCHAIN_EXTERNAL_HEADERS_REALLY_OLD
 
 endchoice
 
+comment "Kernel headers older than 3.13 is not tested by Buildroot. Use at your own risk."
+	depends on !BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_13
+
 choice
 	prompt "External toolchain C library"
 	default BR2_TOOLCHAIN_EXTERNAL_CUSTOM_UCLIBC