diff --git a/6502/C64/Makefile b/6502/C64/Makefile
index f408f61..f331e1b 100644
--- a/6502/C64/Makefile
+++ b/6502/C64/Makefile
@@ -58,7 +58,7 @@ run-testbase16: emulator/testbase16.T64
 
 # Targetcompiler targets
 
-cbmfiles/tcbase: emulator/c64-vf-390.T64 emulator/build-tcbase.sh \
+cbmfiles/tcbase: emulator/v4th-c64-4tc.T64 emulator/build-tcbase.sh \
     disks/tc38q.d64 disks/file-words.d64 cbmfiles/tc-base.fth
 	emulator/build-tcbase.sh
 
diff --git a/6502/C64/cbmfiles/tcbase b/6502/C64/cbmfiles/tcbase
index 857eff9..2fb47ad 100644
Binary files a/6502/C64/cbmfiles/tcbase and b/6502/C64/cbmfiles/tcbase differ
diff --git a/6502/C64/cbmfiles/v4th-c64-4tc b/6502/C64/cbmfiles/v4th-c64-4tc
new file mode 100644
index 0000000..e38a38e
Binary files /dev/null and b/6502/C64/cbmfiles/v4th-c64-4tc differ
diff --git a/6502/C64/emulator/build-tcbase.sh b/6502/C64/emulator/build-tcbase.sh
index db3c513..3e65753 100755
--- a/6502/C64/emulator/build-tcbase.sh
+++ b/6502/C64/emulator/build-tcbase.sh
@@ -14,4 +14,4 @@ keybuf="3 drive 20 load\n3 drive 10 load\nsave\n\
 savesystem tcbase\ndos s0:notdone\n"
 
 DISK10=tc38q DISK11=file-words "${emulatordir}/run-in-vice.sh" \
-  "c64-vf-390" "${keybuf}"
+  "v4th-c64-4tc" "${keybuf}"
diff --git a/6502/C64/emulator/update-v4th-4tc.sh b/6502/C64/emulator/update-v4th-4tc.sh
new file mode 100755
index 0000000..557742c
--- /dev/null
+++ b/6502/C64/emulator/update-v4th-4tc.sh
@@ -0,0 +1,15 @@
+#!/bin/bash
+set -e
+
+# Script to update the base binary on which the target compiler
+# is run.
+
+# The updating of v4th-c64-4tc from the newly built binaries
+# is intentionally not automatically via Makefile, to ensure a
+# certain stability for the target compiler.
+
+emulatordir="$(realpath --relative-to="$PWD" "$(dirname "${BASH_SOURCE[0]}")")"
+basedir="$(realpath --relative-to="$PWD" "${emulatordir}/..")"
+cbmfilesdir="${basedir}/cbmfiles"
+
+cp "${cbmfilesdir}/v4thblk-c64" "${cbmfilesdir}/v4th-c64-4tc"