diff --git a/build/pdp10-ka/config.202 b/build/pdp10-ka/config.202
index 0411b845..cd13704a 100644
--- a/build/pdp10-ka/config.202
+++ b/build/pdp10-ka/config.202
@@ -1246,6 +1246,7 @@ DEFOPT DC10P==0		;1= Has Systems Concepts disk control
 DEFOPT RP10P==0		;1= DEC RP10 disk control (RP02 or RP03)
 DEFOPT RH10P==0		;1= DEC RH10 disk control (RP04 or RP06)
 DEFOPT RH11P==0		;1= DEC RH11 disk control
+DEFOPT RP04P==0		;1= RH10 with RP04's or RP06's
 DEFOPT RP06P==0		;1= RH10 or RH11 with RP06's
 DEFOPT RM03P==0		;1= RH11 with RM03's
 DEFOPT RM80P==0		;1= RH11 with RM80's
diff --git a/build/pdp10-kl/config.202 b/build/pdp10-kl/config.202
index 99de9d52..31173d7c 100644
--- a/build/pdp10-kl/config.202
+++ b/build/pdp10-kl/config.202
@@ -1245,6 +1245,7 @@ DEFOPT DC10P==0		;1= Has Systems Concepts disk control
 DEFOPT RP10P==0		;1= DEC RP10 disk control (RP02 or RP03)
 DEFOPT RH10P==0		;1= DEC RH10 disk control (RP04 or RP06)
 DEFOPT RH11P==0		;1= DEC RH11 disk control
+DEFOPT RP04P==0		;1= RH10 with RP04's or RP06's
 DEFOPT RP06P==0		;1= RH10 or RH11 with RP06's
 DEFOPT RM03P==0		;1= RH11 with RM03's
 DEFOPT RM80P==0		;1= RH11 with RM80's