diff --git a/build/ka10/include.tcl b/build/ka10/include.tcl
index 23bf2175..f67cf041 100644
--- a/build/ka10/include.tcl
+++ b/build/ka10/include.tcl
@@ -1,5 +1,5 @@
 proc start_dskdmp_its {} {
-    start_dskdmp
+    start_dskdmp build/sims/boot
 
     respond "DSKDMP" "its\r"
     expect "\n"; type "\033g"
diff --git a/build/sims/boot2 b/build/sims/boot2
new file mode 100644
index 00000000..0e788944
--- /dev/null
+++ b/build/sims/boot2
@@ -0,0 +1,9 @@
+set cpu its
+set cpu 512k
+set pd off
+at ptr bin/ka10/boot/dskdmp.rim
+at mta0 out/sources.tape
+at dpa0 out/rp03.2
+at dpa1 out/rp03.3
+set dpa noheaders
+b ptr
diff --git a/build/sims/build.tcl b/build/sims/build.tcl
index 764488cf..1230900e 100644
--- a/build/sims/build.tcl
+++ b/build/sims/build.tcl
@@ -6,9 +6,17 @@ proc start_salv {} {
     expect "\n"; send "t\033salv\r"
 }
 
-proc start_dskdmp {} {
+proc start_dskdmp args {
+    puts [llength $args]
     quit_emulator
-    uplevel #0 {spawn ./tools/sims/BIN/ka10 build/sims/boot}
+    set ini ""
+    if {[llength $args] == 1} {
+        set ini [lindex $args 0]
+    } {
+        set ini "build/sims/boot2"
+    }
+    set foo "spawn ./tools/sims/BIN/ka10 $ini"
+    uplevel #0 $foo
 }
 
 proc mount_tape {file} {