diff --git a/doc/comboot.txt b/doc/comboot.txt
index eb43708..13d18f6 100644
--- a/doc/comboot.txt
+++ b/doc/comboot.txt
@@ -949,3 +949,20 @@ AX=0024h [3.80] Cleanup, shuffle and boot, raw version
 	with read/write data segments, matching the respective code
 	segment.  For mode 0, B=0 and the limits will be 64K, for mode
 	1, B=1 and the limits will be 4 GB.
+
+
+AX=0025h [3.84]	Set current working directory
+	Input:	AX	00025h
+		ES:BX	null-terminated directory name string
+	Output:	None
+
+	Sets the current working directory.  For SYSLINUX, ISOLINUX,
+	and PXELINUX, this will be an absolute path.
+
+
+AX=0026h [3.84]	Read file system metadata [ISOLINUX]
+	Input:	AX	00026h
+	Output:	None
+
+	Reads filesystem data (e.g. after a CDROM change).
+
