diff --git a/README.adoc b/README.adoc
index dc7dc1b..98f6392 100644
--- a/README.adoc
+++ b/README.adoc
@@ -13,6 +13,7 @@ This project provides script for making customizable Alpine Linux disk image for
 
 == Requirements
 
+* Linux system with common userland (Busybox or GNU coreutils)
 * POSIX-sh compatible shell (e.g. Busybox ash, dash, Bash, ZSH)
 * qemu-img and qemu-nbd (automatically installed by the script if running on Alpine)
 * e2fsprogs (for ext4), btrfs-progs (for Btrfs), or xfsprogs (for XFS) (automatically installed by the script if running on Alpine)