diff --git a/sbin/sysctl/sysctl.8 b/sbin/sysctl/sysctl.8
index 538a74e94f3f..97baea1f249f 100644
--- a/sbin/sysctl/sysctl.8
+++ b/sbin/sysctl/sysctl.8
@@ -196,6 +196,7 @@ denote
 .It "machdep.console_device	dev_t	no
 .It "machdep.adjkerntz	integer	yes
 .It "machdep.disable_rtc_set	integer	yes
+.It "machdep.guessed_bootdev	string	no
 .It "user.cs_path	string	no
 .It "user.bc_base_max	integer	no
 .It "user.bc_dim_max	integer	no