diff --git a/nixos/doc/manual/from_md/installation/installing-usb.section.xml b/nixos/doc/manual/from_md/installation/installing-usb.section.xml
index b46a1d565557..df266eb16800 100644
--- a/nixos/doc/manual/from_md/installation/installing-usb.section.xml
+++ b/nixos/doc/manual/from_md/installation/installing-usb.section.xml
@@ -17,7 +17,7 @@ $ diskutil list
 [..]
 $ diskutil unmountDisk diskN
 Unmount of all volumes on diskN was successful
-$ sudo dd if=nix.iso of=/dev/rdiskN
+$ sudo dd if=nix.iso of=/dev/rdiskN bs=1M
 </programlisting>
     <para>
       Using the 'raw' <literal>rdiskN</literal> device instead of
diff --git a/nixos/doc/manual/installation/installing-usb.section.md b/nixos/doc/manual/installation/installing-usb.section.md
index ae58c08e5237..d893e22e6381 100644
--- a/nixos/doc/manual/installation/installing-usb.section.md
+++ b/nixos/doc/manual/installation/installing-usb.section.md
@@ -18,7 +18,7 @@ $ diskutil list
 [..]
 $ diskutil unmountDisk diskN
 Unmount of all volumes on diskN was successful
-$ sudo dd if=nix.iso of=/dev/rdiskN
+$ sudo dd if=nix.iso of=/dev/rdiskN bs=1M
 ```
 
 Using the \'raw\' `rdiskN` device instead of `diskN` completes in