diff --git a/cmd/chromedp-gen/build.sh b/cmd/chromedp-gen/build.sh
index fc7179b..398c1f6 100755
--- a/cmd/chromedp-gen/build.sh
+++ b/cmd/chromedp-gen/build.sh
@@ -1,30 +1,8 @@
 #!/bin/bash
 
-UPDATE=0
-LASTUPDATE=0
-if [ -f .last ]; then
-  LASTUPDATE=$(cat .last)
-fi
-
-NOW=$(date +%s)
-if (( "$NOW" >= $(($LASTUPDATE + 86400*5)) )); then
-  UPDATE=1
-fi
-
-if [[ "$UPDATE" == 1 ]]; then
-  go get -u \
-    golang.org/x/tools/cmd/goimports \
-    github.com/mailru/easyjson/easyjson \
-    github.com/valyala/quicktemplate/qtc
-
-  date +%s > .last
-fi
-
 set -ve
 go generate
 
-gofmt -w -s templates/*.go
-
 go build
 
 time ./chromedp-gen $@
diff --git a/cmd/chromedp-gen/domain-gen.go b/cmd/chromedp-gen/domain-gen.go
index b1ac29f..5b9db65 100644
--- a/cmd/chromedp-gen/domain-gen.go
+++ b/cmd/chromedp-gen/domain-gen.go
@@ -61,6 +61,8 @@ func main() {
 const (
 	tpl = `package internal
 
+// AUTOGENERATED. DO NOT EDIT.
+
 import (
 	"fmt"
 	"strconv"
diff --git a/cmd/chromedp-gen/internal/domain.go b/cmd/chromedp-gen/internal/domain.go
index 0f39e42..376623b 100644
--- a/cmd/chromedp-gen/internal/domain.go
+++ b/cmd/chromedp-gen/internal/domain.go
@@ -1,5 +1,7 @@
 package internal
 
+// AUTOGENERATED. DO NOT EDIT.
+
 import (
 	"fmt"
 	"strconv"
diff --git a/cmd/chromedp-gen/main.go b/cmd/chromedp-gen/main.go
index abfd6e5..bb88927 100644
--- a/cmd/chromedp-gen/main.go
+++ b/cmd/chromedp-gen/main.go
@@ -6,6 +6,7 @@ package main
 
 //go:generate go run domain-gen.go
 //go:generate qtc -dir templates -ext qtpl
+//go:generate gofmt -w -s templates/
 
 import (
 	"bytes"
diff --git a/cmd/chromedp-gen/update.sh b/cmd/chromedp-gen/update.sh
index 27eb646..0c59c93 100755
--- a/cmd/chromedp-gen/update.sh
+++ b/cmd/chromedp-gen/update.sh
@@ -22,7 +22,25 @@ curl -s $JS_PROTO | base64 -d > $JS_TMP
 # merge browser_protocol.json and js_protocol.json
 jq -s '[.[] | to_entries] | flatten | reduce .[] as $dot ({}; .[$dot.key] += $dot.value)' $BROWSER_TMP $JS_TMP > $OUT
 
-# convert boolean values listed as strings to real booleans
-# (this is not used in favor of using the custom Bool type that correctly JSON unmarshals the value)
-# left here for completeness
-#perl -pi -e 's/"\s*:\s*"(true|false)"/": \1/g' $OUT
+UPDATE=0
+LASTUPDATE=0
+if [ -f .last ]; then
+  LASTUPDATE=$(cat .last)
+fi
+
+NOW=$(date +%s)
+if (( "$NOW" >= $(($LASTUPDATE + 86400*5)) )); then
+  UPDATE=1
+fi
+
+if [[ "$UPDATE" == 1 ]]; then
+  go get -u -d \
+    github.com/knq/chromedp/cmd/chromedp-gen
+
+  go get -u \
+    golang.org/x/tools/cmd/goimports \
+    github.com/mailru/easyjson/easyjson \
+    github.com/valyala/quicktemplate/qtc
+
+  date +%s > .last
+fi