diff --git a/doc/guix.texi b/doc/guix.texi
index 9b4a096d24b276f358ac7cd1e676017493227061..7baf6ee38a7900e5acd162e695abdbbabb854cbc 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -7320,6 +7320,7 @@ copy the image with:
 
 @example
 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
+sync
 @end example
 
 Access to @file{/dev/sdX} usually requires root privileges.