From 87911a357714144fcd27f7039714e25d2415b708 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Ja=C5=82ocha?= <Pawel.Jalocha@gmail.com>
Date: Thu, 2 Jul 2020 11:26:47 +0100
Subject: [PATCH] Update README.md

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index 93535a0..32bf156 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,7 @@ cd esp-idf
 ```
 If you are doing this on a Raspberry PI and see error messages about *virtualenv* you may need the following:
 ```
+sudo apt-get install libffi-dev
 pip install --upgrade virtualenv==16.7.9
 ```