diff --git a/common/Makefile.inc b/common/Makefile.inc
index 2d18703..ed5f504 100644
--- a/common/Makefile.inc
+++ b/common/Makefile.inc
@@ -107,11 +107,10 @@
 	sed $(GFX_GMA_COMMON_SUBSTITUTIONS) \
 	    -e's/<<CPU>>/$(CONFIG_GFX_GMA_CPU)/' \
 	    -e's/<<CPU_VARIANT>>/$(CONFIG_GFX_GMA_CPU_VARIANT)/' \
-	    -e":s$$(printf '\n ')/,$$/{N;s/,\n.*Dyn_CPU\(_Var\)\?[^,)]*//;ts$$(printf '\n ')P;D;}" \
-	    -e'/Dyn_CPU\(_Var\)\?/d' \
 	    -e's/<\(gen\|$(_GEN_TLA_SUBSTITUTIONS)\(...\)\?\)bool>/constant Boolean/' \
 	    -e's/<\($(_GEN_TLA_SUBSTITUTIONS)\(...\)\?\)var>/constant/' \
 	    -e's/<cpunull>/ is null/' \
+	    -f $(dir $<)/delete_dyncpu.sed \
 	    $< >$@
 endif
 gfxinit-gen-y += $(hw-gfx-gma-config-ads)
diff --git a/common/delete_dyncpu.sed b/common/delete_dyncpu.sed
new file mode 100644
index 0000000..92da9d9
--- /dev/null
+++ b/common/delete_dyncpu.sed
@@ -0,0 +1,11 @@
+# delete `Dyn_CPU` lines along with a preceding comma in the previous line:
+:s
+/,$/{
+        N
+        s/,\n.*Dyn_CPU[^,)]*//
+        ts
+        P
+        D
+}
+# delete all other lines about `Dyn_CPU`:
+/Dyn_CPU/d