diff --git a/doc/mkimage.1 b/doc/mkimage.1
index 800aed4..39652c8 100644
--- a/doc/mkimage.1
+++ b/doc/mkimage.1
@@ -82,12 +82,12 @@
 .B Create FIT image:
 
 .TP
-.BI "\-D "dtc option"
+.BI "\-D [" "dtc options" "]"
 Provide special options to the device tree compiler that is used to
 create the image.
 
 .TP
-.BI "\-f "fit-image.its"
+.BI "\-f [" "image tree source file" "]"
 Image tree source file that describes the structure and contents of the
 FIT image.