diff --git a/INSTALL b/INSTALL
index e325fa2..b92753d 100644
--- a/INSTALL
+++ b/INSTALL
@@ -45,6 +45,7 @@ need the following.
 Prerequisites for make-check:
 
 * qemu, specifically the binary 'qemu-system-i386'
+* xorriso for grub-mkrescue to work
 
 Configuring the GRUB
 ====================