diff --git a/README.md b/README.md
index 5137ed1..b9210bc 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,7 @@ This is a collection of useful buffer modules for C programs.
 *Please see READMEs in the project folders for more details.*
 
 The buffers were developed for embedded microcontrollers (STM32, AVR),
-but can be used anywhere, they are fully portable.
+but can be used anywhere, they are fully portable - only requirement is `malloc()`.
+If you don't have malloc, you'll have to customize the init routines.
 
 Pull requests to add new buffers or improve the current ones are welcome!