diff --git a/ChangeLog b/ChangeLog
index b951405..539b2c8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2018-01-13  Ben Elliston  <bje@gnu.org>
+
+	* config.sub (maybe_os): Remove cases z8k-*-coff and z80-*-coff as
+	these are never matched. Found by Shellcheck.
+
 2018-01-13  Ben Elliston  <bje@gnu.org>
 
 	* config.sub (maybe_os): Remove duplicate m88k-omron* case.
diff --git a/config.sub b/config.sub
index dc850dc..3c2aa6f 100755
--- a/config.sub
+++ b/config.sub
@@ -1263,14 +1263,6 @@ case $basic_machine in
 		basic_machine=ymp-cray
 		os=-unicos
 		;;
-	z8k-*-coff)
-		basic_machine=z8k-unknown
-		os=-sim
-		;;
-	z80-*-coff)
-		basic_machine=z80-unknown
-		os=-sim
-		;;
 	none)
 		basic_machine=none-none
 		os=-none