diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index 11604c9e55e0..60d184677955 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -65,13 +65,18 @@ config DEBUG_USER
 
 # These options are only for real kernel hackers who want to get their hands dirty.
 config DEBUG_LL
-	bool "Kernel low-level debugging functions"
+	bool "Kernel low-level debugging functions (read help!)"
 	depends on DEBUG_KERNEL
 	help
 	  Say Y here to include definitions of printascii, printch, printhex
 	  in the kernel.  This is helpful if you are debugging code that
 	  executes before the console is initialized.
 
+	  Note that selecting this option will limit the kernel to a single
+	  UART definition, as specified below. Attempting to boot the kernel
+	  image on a different platform *will not work*, so this option should
+	  not be enabled for kernels that are intended to be portable.
+
 choice
 	prompt "Kernel low-level debugging port"
 	depends on DEBUG_LL