--- a/doc/Target-utils	Tue Jun 18 05:28:09 2019 +0000
+++ b/doc/Target-utils	Tue Jun 18 06:00:07 2019 +0000
@@ -177,7 +177,10 @@
 one of the ABB commands: abbinit, abbr, abbw or poweroff.  This way if someone
 comes across a Calypso device that has a different ABB type or needs to debug a
 board with broken ABB communication, one can explore other functions without
-touching ABB commands.
+touching ABB commands.  (simtest is another exception: even though it is not
+specific to one particular target device like c139explore, its main function of
+exercising the SIM interface depends on the Iota ABB, thus it is restricted to
+Calypso+Iota targets.)
 
 The abb_init() function invoked by the abbinit command may be invoked multiple
 times: it maintains an internal flag remembering if the initialization steps