diff --git a/Readme.markdown b/Readme.markdown
index ed202fd..c675509 100644
--- a/Readme.markdown
+++ b/Readme.markdown
@@ -27,9 +27,10 @@ Note that there is no one-to-one correspondence between hardware model and AHT.
  Run AHT from bootable USB stick
 ---------------------------------
 
+  * You need a bootable USB stick, for instance using Disk Utility's _Erase_ with `Format: OS X Extended` and `Scheme: GUID Partition Map`.
+  * Let's assume the USB stick is mounted under `/Volumes/USBstick`.
   * Download the AHT for your computer model from the list below.
   * Mount the AHT dmg. Let's refer to the mount point as `/Volumes/AHT`.
-  * Erase and mount a USB stick. Let's assume its mounted under `/Volumes/USBstick`.
   * Copy the AHT to the USB stick and flag it as bootable
 
 ```sh