diff --git a/README.md b/README.md
index f9974f25276151d09c79005326ab7a0d04223c7c..88184eff87a012d311375c41423c2f53dcf0f687 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,8 @@
 [Docker](https://www.docker.com) image based on Centos 7.7 to build E3 modules.
 It includes the yocto ifc14xx and cct cross-compiler toolchains.
 
+The image should use the E3_CROSS_COMPILER_SHORT_SHA as tag by default.
+
 Docker pull command:
 
 ```