diff --git a/recipes/dart.expected/autorun_backtrace.json b/recipes/dart.expected/autorun_backtrace.json
index 78ec5f5..578255b 100644
--- a/recipes/dart.expected/autorun_backtrace.json
+++ b/recipes/dart.expected/autorun_backtrace.json
@@ -247,7 +247,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/dart.expected/failing_tests.json b/recipes/dart.expected/failing_tests.json
index 6019737..97e427a 100644
--- a/recipes/dart.expected/failing_tests.json
+++ b/recipes/dart.expected/failing_tests.json
@@ -247,7 +247,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/dart.expected/goma_dir.json b/recipes/dart.expected/goma_dir.json
index 18fba11..5a79758 100644
--- a/recipes/dart.expected/goma_dir.json
+++ b/recipes/dart.expected/goma_dir.json
@@ -214,7 +214,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=/goma",
diff --git a/recipes/dart.expected/goma_local_cache.json b/recipes/dart.expected/goma_local_cache.json
index cfef5d3..6eaf7ee 100644
--- a/recipes/dart.expected/goma_local_cache.json
+++ b/recipes/dart.expected/goma_local_cache.json
@@ -248,7 +248,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/dart.expected/missing_message.json b/recipes/dart.expected/missing_message.json
index 4082f11..dbb07aa 100644
--- a/recipes/dart.expected/missing_message.json
+++ b/recipes/dart.expected/missing_message.json
@@ -247,7 +247,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/dart.expected/passing_tests.json b/recipes/dart.expected/passing_tests.json
index 3d05d24..6673620 100644
--- a/recipes/dart.expected/passing_tests.json
+++ b/recipes/dart.expected/passing_tests.json
@@ -247,7 +247,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/dart.expected/qemu_failure.json b/recipes/dart.expected/qemu_failure.json
index 5c55971..1ffba28 100644
--- a/recipes/dart.expected/qemu_failure.json
+++ b/recipes/dart.expected/qemu_failure.json
@@ -247,7 +247,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/dart.expected/release.json b/recipes/dart.expected/release.json
index b523cf4..25fe9c7 100644
--- a/recipes/dart.expected/release.json
+++ b/recipes/dart.expected/release.json
@@ -247,7 +247,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/dart.expected/timeout.json b/recipes/dart.expected/timeout.json
index ad3a6ca..692c0e1 100644
--- a/recipes/dart.expected/timeout.json
+++ b/recipes/dart.expected/timeout.json
@@ -247,7 +247,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu",
       "x86-64",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/dart.py b/recipes/dart.py
index a06003d..d6bd9d4 100644
--- a/recipes/dart.py
+++ b/recipes/dart.py
@@ -81,7 +81,7 @@
   with api.step.nest('build fuchsia'):
     with api.goma.build_with_goma(env=goma_env):
       gen_cmd = [
-        api.path['start_dir'].join('packages', 'gn', 'gen.py'),
+        api.path['start_dir'].join('build', 'gn', 'gen.py'),
         '--target_cpu', gn_target,
       ]
 
diff --git a/recipes/fuchsia.expected/arm64_skip_tests.json b/recipes/fuchsia.expected/arm64_skip_tests.json
index 7537cff..00ae42f 100644
--- a/recipes/fuchsia.expected/arm64_skip_tests.json
+++ b/recipes/fuchsia.expected/arm64_skip_tests.json
@@ -229,7 +229,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=aarch64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/autorun_backtrace.json b/recipes/fuchsia.expected/autorun_backtrace.json
index 1b4ed6c..f7c3045 100644
--- a/recipes/fuchsia.expected/autorun_backtrace.json
+++ b/recipes/fuchsia.expected/autorun_backtrace.json
@@ -281,7 +281,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/autorun_failed_qemu.json b/recipes/fuchsia.expected/autorun_failed_qemu.json
index d450190..439a0a6 100644
--- a/recipes/fuchsia.expected/autorun_failed_qemu.json
+++ b/recipes/fuchsia.expected/autorun_failed_qemu.json
@@ -281,7 +281,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/autorun_failed_tests.json b/recipes/fuchsia.expected/autorun_failed_tests.json
index 451da62..6fc7a94 100644
--- a/recipes/fuchsia.expected/autorun_failed_tests.json
+++ b/recipes/fuchsia.expected/autorun_failed_tests.json
@@ -281,7 +281,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/autorun_no_results.json b/recipes/fuchsia.expected/autorun_no_results.json
index 9bcc0b4..cde514e 100644
--- a/recipes/fuchsia.expected/autorun_no_results.json
+++ b/recipes/fuchsia.expected/autorun_no_results.json
@@ -281,7 +281,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/autorun_tests.json b/recipes/fuchsia.expected/autorun_tests.json
index 03cf6e0..367daee 100644
--- a/recipes/fuchsia.expected/autorun_tests.json
+++ b/recipes/fuchsia.expected/autorun_tests.json
@@ -281,7 +281,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/autorun_tests_timeout.json b/recipes/fuchsia.expected/autorun_tests_timeout.json
index f55f398..9e3201a 100644
--- a/recipes/fuchsia.expected/autorun_tests_timeout.json
+++ b/recipes/fuchsia.expected/autorun_tests_timeout.json
@@ -281,7 +281,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/backtrace.json b/recipes/fuchsia.expected/backtrace.json
index 801b3cb..ac150e7 100644
--- a/recipes/fuchsia.expected/backtrace.json
+++ b/recipes/fuchsia.expected/backtrace.json
@@ -261,7 +261,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default,packages/gn/boot_test_runner",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/cq.json b/recipes/fuchsia.expected/cq.json
index 87f78da..c9cf54d 100644
--- a/recipes/fuchsia.expected/cq.json
+++ b/recipes/fuchsia.expected/cq.json
@@ -214,7 +214,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/default.json b/recipes/fuchsia.expected/default.json
index 94c28e3..445e37d 100644
--- a/recipes/fuchsia.expected/default.json
+++ b/recipes/fuchsia.expected/default.json
@@ -229,7 +229,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/failed_tests.json b/recipes/fuchsia.expected/failed_tests.json
index 59b2688..acc2a24 100644
--- a/recipes/fuchsia.expected/failed_tests.json
+++ b/recipes/fuchsia.expected/failed_tests.json
@@ -261,7 +261,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default,packages/gn/boot_test_runner",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/garnet.json b/recipes/fuchsia.expected/garnet.json
index cd658fb..ea38751 100644
--- a/recipes/fuchsia.expected/garnet.json
+++ b/recipes/fuchsia.expected/garnet.json
@@ -231,7 +231,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/gn_args.json b/recipes/fuchsia.expected/gn_args.json
index ba2a6af..f09b6e7 100644
--- a/recipes/fuchsia.expected/gn_args.json
+++ b/recipes/fuchsia.expected/gn_args.json
@@ -214,7 +214,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/fuchsia.expected/goma_local_cache.json b/recipes/fuchsia.expected/goma_local_cache.json
index 9b86dbc..e8a3ba1 100644
--- a/recipes/fuchsia.expected/goma_local_cache.json
+++ b/recipes/fuchsia.expected/goma_local_cache.json
@@ -230,7 +230,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/isolated_tests.json b/recipes/fuchsia.expected/isolated_tests.json
index 693142c..6a3eced 100644
--- a/recipes/fuchsia.expected/isolated_tests.json
+++ b/recipes/fuchsia.expected/isolated_tests.json
@@ -314,7 +314,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/isolated_tests_infra_failure.json b/recipes/fuchsia.expected/isolated_tests_infra_failure.json
index 95b0bc3..7a5f54b 100644
--- a/recipes/fuchsia.expected/isolated_tests_infra_failure.json
+++ b/recipes/fuchsia.expected/isolated_tests_infra_failure.json
@@ -314,7 +314,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/isolated_tests_task_failure.json b/recipes/fuchsia.expected/isolated_tests_task_failure.json
index 4311c65..a9c81e4 100644
--- a/recipes/fuchsia.expected/isolated_tests_task_failure.json
+++ b/recipes/fuchsia.expected/isolated_tests_task_failure.json
@@ -314,7 +314,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--autorun=[TMP_BASE]/autorun",
diff --git a/recipes/fuchsia.expected/lto.json b/recipes/fuchsia.expected/lto.json
index eef9086..777b4c2 100644
--- a/recipes/fuchsia.expected/lto.json
+++ b/recipes/fuchsia.expected/lto.json
@@ -229,7 +229,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/fuchsia.expected/manifest.json b/recipes/fuchsia.expected/manifest.json
index 54966c9..25562b2 100644
--- a/recipes/fuchsia.expected/manifest.json
+++ b/recipes/fuchsia.expected/manifest.json
@@ -214,7 +214,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/no_goma.json b/recipes/fuchsia.expected/no_goma.json
index b1b8224..d5810a8 100644
--- a/recipes/fuchsia.expected/no_goma.json
+++ b/recipes/fuchsia.expected/no_goma.json
@@ -196,7 +196,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=/path/to/goma"
diff --git a/recipes/fuchsia.expected/peridot.json b/recipes/fuchsia.expected/peridot.json
index 82a8bed..8bdb946 100644
--- a/recipes/fuchsia.expected/peridot.json
+++ b/recipes/fuchsia.expected/peridot.json
@@ -256,7 +256,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/release.json b/recipes/fuchsia.expected/release.json
index bd16817..0bb3e05 100644
--- a/recipes/fuchsia.expected/release.json
+++ b/recipes/fuchsia.expected/release.json
@@ -229,7 +229,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/fuchsia.expected/tests.json b/recipes/fuchsia.expected/tests.json
index 3d3dddb..fb34cbe 100644
--- a/recipes/fuchsia.expected/tests.json
+++ b/recipes/fuchsia.expected/tests.json
@@ -261,7 +261,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default,packages/gn/boot_test_runner",
       "--goma=[START_DIR]/cipd/goma"
diff --git a/recipes/fuchsia.expected/thinlto.json b/recipes/fuchsia.expected/thinlto.json
index fccade1..957d891 100644
--- a/recipes/fuchsia.expected/thinlto.json
+++ b/recipes/fuchsia.expected/thinlto.json
@@ -229,7 +229,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/default",
       "--goma=[START_DIR]/cipd/goma",
diff --git a/recipes/fuchsia.py b/recipes/fuchsia.py
index 744097f..f7b8a10 100644
--- a/recipes/fuchsia.py
+++ b/recipes/fuchsia.py
@@ -127,7 +127,7 @@
   with api.step.nest('build fuchsia'):
     with api.goma.build_with_goma(env=goma_env):
       gen_cmd = [
-        api.path['start_dir'].join('packages', 'gn', 'gen.py'),
+        api.path['start_dir'].join('build', 'gn', 'gen.py'),
         '--target_cpu=%s' % gn_target,
         '--packages=%s' % ','.join(modules),
       ]
diff --git a/recipes/sdk.expected/ci.json b/recipes/sdk.expected/ci.json
index e4106a4..18d78ef 100644
--- a/recipes/sdk.expected/ci.json
+++ b/recipes/sdk.expected/ci.json
@@ -226,7 +226,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/sdk",
       "--ignore-skia",
@@ -357,7 +357,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=aarch64",
       "--packages=packages/gn/sdk",
       "--ignore-skia",
diff --git a/recipes/sdk.expected/cq_try.json b/recipes/sdk.expected/cq_try.json
index 115e54d..23a5364 100644
--- a/recipes/sdk.expected/cq_try.json
+++ b/recipes/sdk.expected/cq_try.json
@@ -238,7 +238,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/sdk",
       "--ignore-skia",
@@ -367,7 +367,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=aarch64",
       "--packages=packages/gn/sdk",
       "--ignore-skia",
diff --git a/recipes/sdk.expected/no_goma.json b/recipes/sdk.expected/no_goma.json
index c35d9f3..6477450 100644
--- a/recipes/sdk.expected/no_goma.json
+++ b/recipes/sdk.expected/no_goma.json
@@ -176,7 +176,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=packages/gn/sdk",
       "--ignore-skia",
@@ -206,7 +206,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=aarch64",
       "--packages=packages/gn/sdk",
       "--ignore-skia",
diff --git a/recipes/sdk.py b/recipes/sdk.py
index ce8912a..d0d7d78 100644
--- a/recipes/sdk.py
+++ b/recipes/sdk.py
@@ -74,7 +74,7 @@
                  modules, use_goma, gn_args):
   with api.step.nest('build fuchsia %s' % gn_target), GomaContext(api, use_goma):
     gen_cmd = [
-        api.path['start_dir'].join('packages', 'gn', 'gen.py'),
+        api.path['start_dir'].join('build', 'gn', 'gen.py'),
         '--target_cpu=%s' % gn_target,
         '--packages=%s' % ','.join(modules),
         '--ignore-skia'
diff --git a/recipes/web_view.expected/default.json b/recipes/web_view.expected/default.json
index 9118952..c505e3d 100644
--- a/recipes/web_view.expected/default.json
+++ b/recipes/web_view.expected/default.json
@@ -214,7 +214,7 @@
   },
   {
     "cmd": [
-      "[START_DIR]/packages/gn/gen.py",
+      "[START_DIR]/build/gn/gen.py",
       "--target_cpu=x86-64",
       "--packages=topaz/packages/webkit",
       "--args",
diff --git a/recipes/web_view.py b/recipes/web_view.py
index 6c2dfc4..1cc27ad 100644
--- a/recipes/web_view.py
+++ b/recipes/web_view.py
@@ -63,7 +63,7 @@
 
   with api.step.nest('build fuchsia'), api.goma.build_with_goma():
     api.step('gen', [
-      api.path['start_dir'].join('packages/gn/gen.py'),
+      api.path['start_dir'].join('build/gn/gen.py'),
       '--target_cpu=%s' % gen_target,
       '--packages=topaz/packages/webkit',
       '--args', 'use_prebuilt_webkit=false',