diff --git a/config/data/coreboot/mkhelper.cfg b/config/data/coreboot/mkhelper.cfg
index c23ebdf..a1c48e6 100644
--- a/config/data/coreboot/mkhelper.cfg
+++ b/config/data/coreboot/mkhelper.cfg
@@ -9,5 +9,6 @@ v="$v displaymode tmprom"
 eval `setvars "n" $pv`
 eval `setvars "" $v`
 
+premake="mkvendorfiles"
 mkhelper="mkcorebootbin"
 postmake="mkcoreboottar"
diff --git a/include/rom.sh b/include/rom.sh
index a0a1c9e..a4080a5 100644
--- a/include/rom.sh
+++ b/include/rom.sh
@@ -8,6 +8,7 @@
 
 mkserprog()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run
 	basename -as .h "$serdir/"*.h > "$TMPDIR/ser" || $err "!mk $1 $TMPDIR"
 
 	while read -r sertarget; do
@@ -25,6 +26,7 @@ mkserprog()
 
 mkpayload_grub()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run
 	eval `setvars "" grub_modules grub_install_modules`
 	eval `setcfg "$grubdata/module/$tree"`
 
@@ -40,8 +42,33 @@ mkpayload_grub()
 	    $err "$tree: cannot build grub.elf"; return 0
 }
 
+check_coreboot_utils()
+{
+	for util in cbfstool ifdtool; do
+		utilelfdir="elf/$util/$1"
+		utilsrcdir="src/coreboot/$1/util/$util"
+
+		utilmode="" && [ -n "$mode" ] && utilmode="clean"
+		x_ make -C "$utilsrcdir" $utilmode -j$XBMK_THREADS $makeargs
+		[ -z "$mode" ] && [ ! -f "$utilelfdir/$util" ] && \
+			x_ mkdir -p "$utilelfdir" && \
+			x_ cp "$utilsrcdir/$util" "elf/$util/$1"
+		[ -z "$mode" ] || x_ rm -Rf "$utilelfdir"; continue
+	done; return 0
+}
+
+mkvendorfiles()
+{
+	if [ "$_f" = "-d" ]; then
+		check_coreboot_utils "$tree"
+	elif [ "$_f" = "-b" ]; then
+		printf "%s\n" "${version%%-*}" > "$cdir/.coreboot-version"
+	fi
+}
+
 mkcorebootbin()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run
 	[ "$target" = "$tree" ] && return 0
 
 	tmprom="$cdir/build/coreboot.rom"
@@ -64,7 +91,7 @@ mkcorebootbin()
 	[ "$payload_memtest" = "y" ] || payload_memtest="n"
 	[ "$(uname -m)" = "x86_64" ] || payload_memtest="n"
 
-	x_ ./update trees -b coreboot utils $tree
+	x_ ./update trees -d coreboot $tree
 
 	[ "$payload_seabios" = "y" ] && pname="seabios" && add_seabios
 	[ "$payload_uboot" = "y" ] && pname="uboot" && add_uboot
@@ -113,6 +140,7 @@ add_uboot()
 
 mkcoreboottar()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run
 	[ "$target" = "$tree" ] && return 0; [ "$XBMK_RELEASE" = "y" ] && \
 	    [ "$release" != "n" ] && mkrom_tarball "bin/$target"; return 0
 }
diff --git a/script/trees b/script/trees
index 7765683..c617598 100755
--- a/script/trees
+++ b/script/trees
@@ -14,16 +14,17 @@ set -u -e
 . "config/data/coreboot/mkhelper.cfg"
 
 eval `setvars "" xarch cdir defconfig cmakedir xlang mode makeargs elfdir cmd \
-    project target target_dir targets xtree _f target1 bootstrapargs mkhelper \
+    project target target_dir targets xtree _f release bootstrapargs mkhelper \
     autoconfargs listfile autogenargs btype tree rev tree_depend build_depend \
-    premake release postmake`
+    premake postmake`
 
 main()
 {
-	while getopts f:b:m:u:c:x:s:l:n: option; do
+	while getopts f:b:m:u:c:x:s:l:n:d: option; do
 		[ -n "$_f" ] && $err "only one flag is permitted"
 		_f="$1"
 		case "$1" in
+		-d) mode="" ;;
 		-b) mode="" ;;
 		-u) mode="oldconfig" ;;
 		-m) mode="menuconfig" ;;
@@ -58,10 +59,9 @@ main()
 	cmd="build_targets" && singletree "$project" && cmd="build_project"
 	$cmd $@
 
-	[ "$target1" = "utils" ] && [ "$project" = "coreboot" ] && return 0
-
 	[ -f "$listfile" ] || return 0
-	[ -z "$mode" ] && printf "\n\nOK! Check %s/\n\n" "$elfdir"; return 0
+	[ -z "$mode" ] && [ "$_f" = "-b" ] && \
+	    printf "\n\nOK! Check %s/\n\n" "$elfdir"; return 0
 }
 
 build_project()
@@ -85,8 +85,6 @@ build_targets()
 	[ -d "$cfgsdir" ] || $err "directory, $cfgsdir, does not exist"
 
 	# Build for all targets if no argument is given
-	[ $# -gt 0 ] && target1="$1"
-	[ "$target1" = "utils" ] && [ "$project" = "coreboot" ] && shift 1
 	targets="$(ls -1 "$cfgsdir")" || $err "Can't get options for $cfgsdir"
 	[ $# -gt 0 ] && targets=$@
 
@@ -110,12 +108,9 @@ handle_defconfig()
 {
 	handle_src_tree "$target" || return 0
 
-	[ "$target1" = "utils" ] && [ "$project" = "coreboot" ] && \
-		eval "check_coreboot_utils \"$tree\"; return 0"
-
 	for y in "$target_dir/config"/*; do
-		[ -f "$y" ] || continue
-		defconfig="$y"
+		[ "$_f" = "-d" ] || [ -f "$y" ] || continue
+		[ "$_f" = "-d" ] || defconfig="$y"
 
 		[ -n "$mode" ] || check_defconfig || continue
 		handle_makefile
@@ -139,8 +134,7 @@ handle_src_tree()
 	fi
 	x_ ./update trees -f "$project" "$target"
 
-	[ "$target1" = "utils" ] && [ "$project" = "coreboot" ] && return 0
-	[ -z "$mode" ] && check_cross_compiler; return 0
+	[ -z "$mode" ] && [ "$_f" = "-b" ] && check_cross_compiler; return 0
 }
 
 configure_project()
@@ -156,6 +150,8 @@ configure_project()
 
 		printf "Loading %s config: %s\n" "$project" "$_tcfg"
 		eval `setcfg "$_tcfg"`
+
+		[ "$_f" = "-d" ] && build_depend="" # dry run
 		[ "$cmd" = "build_project" ] && break
 		[ "$mode" = "fetch" ] || break
 
@@ -166,13 +162,18 @@ configure_project()
 	[ "$XBMK_RELEASE" = "y" ] && [ "$release" = "n" ] && return 1
 	[ -z "$btype" ] || [ "${mode%config}" = "$mode" ] || return 1
 
-	[ -z "$mode" ] && for bd in $build_depend; do
-		bd_project="${bd%%/*}"; bd_tree="${bd##*/}"
-		[ -z "$bd_project" ] && $err "$project/$tree: bad bd: '$bd'"
-		[ "${bd##*/}" = "$bd" ] && bd_tree=""
-		[ -z "$bd_project" ] || ./update trees -b $bd_project \
-		    $bd_tree || $err "$project/$tree: !bd $bd"; continue
-	done
+	if [ "$_f" != "-d" ]; then
+		:
+	elif [ -z "$mode" ]; then
+		for bd in $build_depend; do
+			bd_project="${bd%%/*}"; bd_tree="${bd##*/}"
+			[ -z "$bd_project" ] && \
+			    $err "$project/$tree: bad bd: '$bd'"
+			[ "${bd##*/}" = "$bd" ] && bd_tree=""
+			[ -z "$bd_project" ] || ./update trees -b $bd_project \
+			    $bd_tree || $err "$project/$tree: !bd $bd"
+		done
+	fi
 
 	[ "$mode" = "fetch" ] || return 0
 	[ -f "CHANGELOG" ] && return 1; fetch_${cmd#build_}; return 1
@@ -198,23 +199,9 @@ check_cross_compiler()
 	done; return 0
 }
 
-check_coreboot_utils()
-{
-	for util in cbfstool ifdtool; do
-		utilelfdir="elf/$util/$1"
-		utilsrcdir="src/coreboot/$1/util/$util"
-
-		utilmode="" && [ -n "$mode" ] && utilmode="clean"
-		x_ make -C "$utilsrcdir" $utilmode -j$XBMK_THREADS $makeargs
-		[ -z "$mode" ] && [ ! -f "$utilelfdir/$util" ] && \
-			x_ mkdir -p "$utilelfdir" && \
-			x_ cp "$utilsrcdir/$util" "elf/$util/$1"
-		[ -z "$mode" ] || x_ rm -Rf "$utilelfdir"
-	done; return 0
-}
-
 check_defconfig()
 {
+	[ "$_f" = "-d" ] && return 0
 	[ -f "$defconfig" ] || $err "$project/$target: missing defconfig"
 
 	dest_dir="$elfdir/$target/${defconfig#"$target_dir/config/"}"
@@ -225,6 +212,8 @@ check_defconfig()
 
 elfcheck()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run. assume a build exists.
+
 	# TODO: very hacky check. do it properly (based on build.list)
 	for elftest in "$dest_dir"/*; do
 		[ -e "$elftest" ] && e "$elftest" f && return 1
@@ -234,11 +223,12 @@ elfcheck()
 handle_makefile()
 {
 	check_makefile "$cdir" && x_ make clean -C "$cdir"
-	x_ cp "$defconfig" "$cdir/.config"
-	[ -n "$mode" ] || [ -n "$btype" ] || make -C "$cdir" \
-	    silentoldconfig || make -C "$cdir" oldconfig || :
+	[ -f "$defconfig" ] && x_ cp "$defconfig" "$cdir/.config"
+	[ "$_f" = "-d" ] || [ -n "$mode" ] || [ -n "$btype" ] || make -C \
+	    "$cdir" silentoldconfig || make -C "$cdir" oldconfig || :
 
 	run_make_command || $err "handle_makefile $cdir: no makefile!"
+	[ "$_f" = "-d" ] && return 0
 
 	_copy=".config" && [ "$mode" = "savedefconfig" ] && _copy="defconfig"
 	[ "${mode%config}" = "$mode" ] || x_ cp "$cdir/$_copy" "$defconfig"
@@ -254,17 +244,17 @@ run_make_command()
 	check_cmake "$cdir" && [ -z "$mode" ] && check_autoconf "$cdir"
 	check_makefile "$cdir" || return 1
 
-	[ "$project" = "coreboot" ] && [ -z "$mode" ] && x_ \
-		printf "%s\n" "${version%%-*}" > "$cdir/.coreboot-version"
-
-	make -C "$cdir" $mode -j$XBMK_THREADS $makeargs || $err "$cdir mk$mode"
+	[ "$_f" = "-d" ] || make -C "$cdir" $mode -j$XBMK_THREADS $makeargs \
+	    || $err "$cdir mk$mode"
 	[ -z "$mkhelper" ] || [ -n "$mode" ] || $mkhelper || $err "!$mkhelper"
 
+	[ "$_f" = "-d" ] && return 0
 	[ "$mode" = "clean" ] && make -C "$cdir" distclean || :; return 0
 }
 
 check_cmake()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run
 	[ -z "$cmakedir" ] || check_makefile "$1" || cmake -B "$1" \
 	    "$1/$cmakedir" || check_makefile "$1" || $err "$1: !cmk $cmakedir"
 	[ -z "$cmakedir" ] || check_makefile "$1" || \
@@ -273,6 +263,7 @@ check_cmake()
 
 check_autoconf()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run
 	(
 	cd "$1" || $err "!cd $1"
 	[ -f "bootstrap" ] && x_ ./bootstrap $bootstrapargs
@@ -283,12 +274,14 @@ check_autoconf()
 
 check_makefile()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run
 	[ -f "$1/Makefile" ] || [ -f "$1/makefile" ] || \
 	    [ -f "$1/GNUmakefile" ] || return 1; return 0
 }
 
 copy_elf()
 {
+	[ "$_f" = "-d" ] && return 0 # dry run
 	[ -f "$listfile" ] && x_ mkdir -p "$dest_dir" && while read -r f; do
 		[ -f "$cdir/$f" ] && x_ cp "$cdir/$f" "$dest_dir"
 	done < "$listfile"; x_ make clean -C "$cdir"