diff --git a/Makefile b/Makefile
index f7dd44e9..d56c9ff2 100644
--- a/Makefile
+++ b/Makefile
@@ -9,13 +9,16 @@ WRITETAPE=${PWD}/tools/tapeutils/tapewrite
 
 all: out/rp0.dsk
 
-out/rp0.dsk: build/simh/init out/minsys.tape out/salv.tape out/dskdmp.tape build/build.tcl
+out/rp0.dsk: build/simh/init out/minsys.tape out/salv.tape out/dskdmp.tape build/build.tcl out/sources.tape
 	expect -f build/build.tcl
 
 out/minsys.tape: $(ITSTAR)
 	mkdir -p out
 	cd bin; $(ITSTAR) -cf ../$@ $(MINSYS)
-	cd src; $(ITSTAR) -rf ../$@ $(SRC)
+
+out/sources.tape: $(ITSTAR)
+	mkdir -p out
+	cd src; $(ITSTAR) -cf ../$@ $(SRC)
 
 out/salv.tape: $(WRITETAPE) $(RAM) $(NSALV)
 	mkdir -p out
diff --git a/README.md b/README.md
index c98b3365..cc835117 100644
--- a/README.md
+++ b/README.md
@@ -20,14 +20,14 @@ This repository contains source code, tools, and scripts to build ITS
 from scratch.
 
 1. First, magnetic tape images are created from files in `src` and
-   `bin`.  There are two bootable tapes, and one tape with files in
+   `bin`.  There are two bootable tapes, and two tapes with files in
    DUMP backup format.
 
 2. Then the tapes are used to create a file system on an RP06 disk and
-   populate it with a minimal system, and also source code.
+   populate it with a minimal system.
 
-3. Next, the system is booted from the disk, and the following programs
-   are rebuilt:
+3. Next, the system is booted from the disk.  Source code is loaded
+   from tape, and the following programs are rebuilt:
 
    - MIDAS, the assembler.
    - DDT, debugger and HACTRN user login shell.
diff --git a/bin/sys/ts.dump b/bin/sys/ts.dump
new file mode 100644
index 00000000..2ba32ab3
Binary files /dev/null and b/bin/sys/ts.dump differ
diff --git a/build/build.tcl b/build/build.tcl
index e331ca90..47dfe8d2 100644
--- a/build/build.tcl
+++ b/build/build.tcl
@@ -94,6 +94,19 @@ spawn pdp10 build/simh/boot
 respond "DSKDMP" "its\r"
 type "\033g"
 pdset
+
+respond "*" "\005"
+respond "sim>" "at tu0 out/sources.tape\r"
+respond "sim>" "c\r"
+type ":dump\r"
+respond "_" "reload "
+respond "ARE YOU SURE" "y"
+respond "\n" "links crdir sorry\r"
+respond "FILE=" "*;* *\r"
+expect "E-O-T"
+respond "_" "quit\r"
+expect ":KILL"
+
 respond "*" ":print sysbin;..new. (udir)\r"
 respond "*" ":midas sysbin;_midas;midas\r"
 expect ":KILL"
@@ -129,7 +142,8 @@ respond "*" ":link sys3;ts teco,.teco.;tecpur >\r"
 respond "*" ":midas sysbin;_syseng;dump\r"
 respond "WHICH MACHINE?" "DB\r"
 expect ":KILL"
-respond "*" ":link sys3;ts dump,sysbin;dump bin\r"
+respond "*" ":delete sys;ts dump\r"
+respond "*" ":link sys;ts dump,sysbin;dump bin\r"
 
 respond "*" ":midas sysbin;_sysen1;pdset\r"
 expect ":KILL"