diff --git a/recipes/README.recipes.md b/recipes/README.recipes.md
index 96cf050e4..0a0666266 100644
--- a/recipes/README.recipes.md
+++ b/recipes/README.recipes.md
@@ -40,20 +40,20 @@
 
 Recipe module to ensure a checkout is consistent on a bot.
 
-#### **class [BotUpdateApi](/recipes/recipe_modules/bot_update/api.py#11)([RecipeApi][recipe_engine/wkt/RecipeApi]):**
+#### **class [BotUpdateApi](/recipes/recipe_modules/bot_update/api.py#10)([RecipeApi][recipe_engine/wkt/RecipeApi]):**
 
-— **def [\_\_call\_\_](/recipes/recipe_modules/bot_update/api.py#32)(self, name, cmd, \*\*kwargs):**
+— **def [\_\_call\_\_](/recipes/recipe_modules/bot_update/api.py#31)(self, name, cmd, \*\*kwargs):**
 
 Wrapper for easy calling of bot_update.
 
-— **def [apply\_gerrit\_ref](/recipes/recipe_modules/bot_update/api.py#47)(self, root, gerrit_no_reset=False, gerrit_no_rebase_patch_ref=False, gerrit_repo=None, gerrit_ref=None, step_name='apply_gerrit', \*\*kwargs):**
+— **def [apply\_gerrit\_ref](/recipes/recipe_modules/bot_update/api.py#46)(self, root, gerrit_no_reset=False, gerrit_no_rebase_patch_ref=False, gerrit_repo=None, gerrit_ref=None, step_name='apply_gerrit', \*\*kwargs):**
 
-— **def [deapply\_patch](/recipes/recipe_modules/bot_update/api.py#399)(self, bot_update_step):**
+— **def [deapply\_patch](/recipes/recipe_modules/bot_update/api.py#410)(self, bot_update_step):**
 
 Deapplies a patch, taking care of DEPS and solution revisions properly.
     
 
-— **def [ensure\_checkout](/recipes/recipe_modules/bot_update/api.py#69)(self, gclient_config=None, suffix=None, patch=True, update_presentation=True, patch_root=None, no_shallow=False, with_branch_heads=False, with_tags=False, refs=None, patch_oauth2=None, oauth2_json=None, use_site_config_creds=None, clobber=False, root_solution_revision=None, rietveld=None, issue=None, patchset=None, gerrit_no_reset=False, gerrit_no_rebase_patch_ref=False, disable_syntax_validation=False, manifest_name=None, \*\*kwargs):**
+— **def [ensure\_checkout](/recipes/recipe_modules/bot_update/api.py#68)(self, gclient_config=None, suffix=None, patch=True, update_presentation=True, patch_root=None, no_shallow=False, with_branch_heads=False, with_tags=False, refs=None, patch_oauth2=None, oauth2_json=None, use_site_config_creds=None, clobber=False, root_solution_revision=None, rietveld=None, issue=None, patchset=None, gerrit_no_reset=False, gerrit_no_rebase_patch_ref=False, disable_syntax_validation=False, manifest_name=None, \*\*kwargs):**
 
 Args:
   gclient_config: The gclient configuration to use when running bot_update.
@@ -64,7 +64,7 @@ Args:
   manifest_name: The name of the manifest to upload to LogDog.  This must
     be unique for the whole build.
 
-— **def [get\_project\_revision\_properties](/recipes/recipe_modules/bot_update/api.py#376)(self, project_name, gclient_config=None):**
+— **def [get\_project\_revision\_properties](/recipes/recipe_modules/bot_update/api.py#387)(self, project_name, gclient_config=None):**
 
 Returns all property names used for storing the checked-out revision of
 a given project.
@@ -78,7 +78,7 @@ Args:
 Returns (list of str): All properties that'll hold the checked-out revision
     of the given project. An empty list if no such properties exist.
 
-&emsp; **@property**<br>&mdash; **def [last\_returned\_properties](/recipes/recipe_modules/bot_update/api.py#41)(self):**
+&emsp; **@property**<br>&mdash; **def [last\_returned\_properties](/recipes/recipe_modules/bot_update/api.py#40)(self):**
 ### *recipe_modules* / [cipd](/recipes/recipe_modules/cipd)
 
 [DEPS](/recipes/recipe_modules/cipd/__init__.py#1): [infra\_paths](#recipe_modules-infra_paths), [recipe\_engine/json][recipe_engine/recipe_modules/json], [recipe\_engine/path][recipe_engine/recipe_modules/path], [recipe\_engine/platform][recipe_engine/recipe_modules/platform], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/python][recipe_engine/recipe_modules/python], [recipe\_engine/raw\_io][recipe_engine/recipe_modules/raw_io], [recipe\_engine/step][recipe_engine/recipe_modules/step]
diff --git a/recipes/recipe_modules/bot_update/api.py b/recipes/recipe_modules/bot_update/api.py
index ffe39bf83..87c238fa7 100644
--- a/recipes/recipe_modules/bot_update/api.py
+++ b/recipes/recipe_modules/bot_update/api.py
@@ -190,6 +190,14 @@ class BotUpdateApi(recipe_api.RecipeApi):
           refs.append(fixed_revision.split(':')[0])
         flags.append(['--revision', '%s@%s' % (name, fixed_revision)])
 
+    for ref in refs:
+      assert not ref.startswith('refs/remotes/'), (
+          'The "refs/remotes/*" syntax is not supported.\n'
+          'The "remotes" syntax is dependent on the way the local repo is '
+          'configured, and while there are defaults that can often be '
+          'assumed, there is no guarantee the mapping will always be done in '
+          'a particular way.')
+
     # Add extra fetch refspecs.
     for ref in refs:
       flags.append(['--refs', ref])