diff --git a/tools/binman/README.entries b/tools/binman/README.entries
index 5cb52a9..091fb5c 100644
--- a/tools/binman/README.entries
+++ b/tools/binman/README.entries
@@ -26,6 +26,15 @@
 
 
 
+Entry: blob-dtb: A blob that holds a device tree
+------------------------------------------------
+
+This is a blob containing a device tree. The contents of the blob are
+obtained from the list of available device-tree files, managed by the
+'state' module.
+
+
+
 Entry: blob-named-by-arg: A blob entry which gets its filename property from its subclass
 -----------------------------------------------------------------------------------------
 
@@ -309,6 +318,9 @@
 U-Boot. U-Boot needs this to know what devices are present and which drivers
 to activate.
 
+Note: This is mostly an internal entry type, used by others. This allows
+binman to know which entries contain a device tree.
+
 
 
 Entry: u-boot-dtb-with-ucode: A U-Boot device tree file, with the microcode removed