diff --git a/tools/roomservice.py b/tools/roomservice.py
index 61f8555..f5aac06 100755
--- a/tools/roomservice.py
+++ b/tools/roomservice.py
@@ -1,55 +1,275 @@
 #!/usr/bin/env python
+# Copyright (C) 2012-2013, The CyanogenMod Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 import os
 import sys
 import urllib2
 import json
+import re
+import netrc, base64
 from xml.etree import ElementTree
 
 product = sys.argv[1];
-device = product[product.index("_") + 1:]
-print "Device %s not found. Attempting to retrieve device repository from CyanogenMod Github (http://github.com/CyanogenMod)." % device
+
+if len(sys.argv) > 2:
+    depsonly = sys.argv[2]
+else:
+    depsonly = None
+
+try:
+    device = product[product.index("_") + 1:]
+except:
+    device = product
+
+if not depsonly:
+    print "Device %s not found. Attempting to retrieve device repository from CyanogenMod Github (http://github.com/CyanogenMod)." % device
 
 repositories = []
 
+try:
+    authtuple = netrc.netrc().authenticators("api.github.com")
+
+    if authtuple:
+        githubauth = base64.encodestring('%s:%s' % (authtuple[0], authtuple[2])).replace('\n', '')
+    else:
+        githubauth = None
+except:
+    githubauth = None
+
+def add_auth(githubreq):
+    if githubauth:
+        githubreq.add_header("Authorization","Basic %s" % githubauth)
+
 page = 1
-while True:
-    result = json.loads(urllib2.urlopen("http://github.com/api/v2/json/repos/show/CyanogenMod?page=%d" % page).read())
-    if len(result['repositories']) == 0:
+while not depsonly:
+    githubreq = urllib2.Request("https://api.github.com/users/CyanogenMod/repos?per_page=200&page=%d" % page)
+    add_auth(githubreq)
+    result = json.loads(urllib2.urlopen(githubreq).read())
+    if len(result) == 0:
         break
-    repositories = repositories + result['repositories']
+    for res in result:
+        repositories.append(res)
     page = page + 1
 
-for repository in repositories:
-    repo_name = repository['name']
-    if repo_name.startswith("android_device_") and repo_name.endswith("_" + device):
-        print "Found repository: %s" % repository['name']
-        manufacturer = repo_name.replace("android_device_", "").replace("_" + device, "")
-        
-        try:
-            lm = ElementTree.parse(".repo/local_manifest.xml")
-            lm = lm.getroot()
-        except:
-            lm = ElementTree.Element("manifest")
-        
-        for child in lm.getchildren():
-            if child.attrib['name'].endswith("_" + device):
-                print "Duplicate device '%s' found in local_manifest.xml." % child.attrib['name']
-                sys.exit()
+local_manifests = r'.repo/local_manifests'
+if not os.path.exists(local_manifests): os.makedirs(local_manifests)
 
-        repo_path = "device/%s/%s" % (manufacturer, device)
-        project = ElementTree.Element("project", attrib = { "path": repo_path, "remote": "github", "name": "CyanogenMod/%s" % repository['name'] })
+def exists_in_tree(lm, repository):
+    for child in lm.getchildren():
+        if child.attrib['name'].endswith(repository):
+            return True
+    return False
+
+# in-place prettyprint formatter
+def indent(elem, level=0):
+    i = "\n" + level*"  "
+    if len(elem):
+        if not elem.text or not elem.text.strip():
+            elem.text = i + "  "
+        if not elem.tail or not elem.tail.strip():
+            elem.tail = i
+        for elem in elem:
+            indent(elem, level+1)
+        if not elem.tail or not elem.tail.strip():
+            elem.tail = i
+    else:
+        if level and (not elem.tail or not elem.tail.strip()):
+            elem.tail = i
+
+def get_default_revision():
+    m = ElementTree.parse(".repo/manifest.xml")
+    d = m.findall('default')[0]
+    r = d.get('revision')
+    return r.replace('refs/heads/', '').replace('refs/tags/', '')
+
+def get_from_manifest(devicename):
+    try:
+        lm = ElementTree.parse(".repo/local_manifests/roomservice.xml")
+        lm = lm.getroot()
+    except:
+        lm = ElementTree.Element("manifest")
+
+    for localpath in lm.findall("project"):
+        if re.search("android_device_.*_%s$" % device, localpath.get("name")):
+            return localpath.get("path")
+
+    # Devices originally from AOSP are in the main manifest...
+    try:
+        mm = ElementTree.parse(".repo/manifest.xml")
+        mm = mm.getroot()
+    except:
+        mm = ElementTree.Element("manifest")
+
+    for localpath in mm.findall("project"):
+        if re.search("android_device_.*_%s$" % device, localpath.get("name")):
+            return localpath.get("path")
+
+    return None
+
+def is_in_manifest(projectname):
+    try:
+        lm = ElementTree.parse(".repo/local_manifests/roomservice.xml")
+        lm = lm.getroot()
+    except:
+        lm = ElementTree.Element("manifest")
+
+    for localpath in lm.findall("project"):
+        if localpath.get("name") == projectname:
+            return 1
+
+    ## Search in main manifest, too
+    try:
+        lm = ElementTree.parse(".repo/manifest.xml")
+        lm = lm.getroot()
+    except:
+        lm = ElementTree.Element("manifest")
+
+    for localpath in lm.findall("project"):
+        if localpath.get("name") == projectname:
+            return 1
+
+    return None
+
+def add_to_manifest(repositories, fallback_branch = None):
+    try:
+        lm = ElementTree.parse(".repo/local_manifests/roomservice.xml")
+        lm = lm.getroot()
+    except:
+        lm = ElementTree.Element("manifest")
+
+    for repository in repositories:
+        repo_name = repository['repository']
+        repo_target = repository['target_path']
+        if exists_in_tree(lm, repo_name):
+            print 'CyanogenMod/%s already exists' % (repo_name)
+            continue
+
+        print 'Adding dependency: CyanogenMod/%s -> %s' % (repo_name, repo_target)
+        project = ElementTree.Element("project", attrib = { "path": repo_target,
+            "remote": "github", "name": "CyanogenMod/%s" % repo_name })
+
+        if 'branch' in repository:
+            project.set('revision',repository['branch'])
+        elif fallback_branch:
+            print "Using fallback branch %s for %s" % (fallback_branch, repo_name)
+            project.set('revision', fallback_branch)
+        else:
+            print "Using default branch for %s" % repo_name
+
         lm.append(project)
-        
-        raw_xml = ElementTree.tostring(lm)
-        raw_xml = '<?xml version="1.0" encoding="UTF-8"?>\n' + raw_xml
 
-        f = open('.repo/local_manifest.xml', 'w')
-        f.write(raw_xml)
-        f.close()
-        
-        print "Syncing repository to retrieve project."
-        os.system('repo sync %s' % repo_path)
-        print "Done!"
-        sys.exit()
+    indent(lm, 0)
+    raw_xml = ElementTree.tostring(lm)
+    raw_xml = '<?xml version="1.0" encoding="UTF-8"?>\n' + raw_xml
 
-print "Repository for %s not found in the CyanogenMod Github repository list. If this is in error, you may need to manually add it to your local_manifest.xml." % device
+    f = open('.repo/local_manifests/roomservice.xml', 'w')
+    f.write(raw_xml)
+    f.close()
+
+def fetch_dependencies(repo_path, fallback_branch = None):
+    print 'Looking for dependencies'
+    dependencies_path = repo_path + '/cm.dependencies'
+    syncable_repos = []
+
+    if os.path.exists(dependencies_path):
+        dependencies_file = open(dependencies_path, 'r')
+        dependencies = json.loads(dependencies_file.read())
+        fetch_list = []
+
+        for dependency in dependencies:
+            if not is_in_manifest("CyanogenMod/%s" % dependency['repository']):
+                fetch_list.append(dependency)
+                syncable_repos.append(dependency['target_path'])
+
+        dependencies_file.close()
+
+        if len(fetch_list) > 0:
+            print 'Adding dependencies to manifest'
+            add_to_manifest(fetch_list, fallback_branch)
+    else:
+        print 'Dependencies file not found, bailing out.'
+
+    if len(syncable_repos) > 0:
+        print 'Syncing dependencies'
+        os.system('repo sync %s' % ' '.join(syncable_repos))
+
+    for deprepo in syncable_repos:
+        fetch_dependencies(deprepo)
+
+def has_branch(branches, revision):
+    return revision in [branch['name'] for branch in branches]
+
+if depsonly:
+    repo_path = get_from_manifest(device)
+    if repo_path:
+        fetch_dependencies(repo_path)
+    else:
+        print "Trying dependencies-only mode on a non-existing device tree?"
+
+    sys.exit()
+
+else:
+    for repository in repositories:
+        repo_name = repository['name']
+        if repo_name.startswith("android_device_") and repo_name.endswith("_" + device):
+            print "Found repository: %s" % repository['name']
+            
+            manufacturer = repo_name.replace("android_device_", "").replace("_" + device, "")
+            
+            default_revision = get_default_revision()
+            print "Default revision: %s" % default_revision
+            print "Checking branch info"
+            githubreq = urllib2.Request(repository['branches_url'].replace('{/branch}', ''))
+            add_auth(githubreq)
+            result = json.loads(urllib2.urlopen(githubreq).read())
+
+            ## Try tags, too, since that's what releases use
+            if not has_branch(result, default_revision):
+                githubreq = urllib2.Request(repository['tags_url'].replace('{/tag}', ''))
+                add_auth(githubreq)
+                result.extend (json.loads(urllib2.urlopen(githubreq).read()))
+            
+            repo_path = "device/%s/%s" % (manufacturer, device)
+            adding = {'repository':repo_name,'target_path':repo_path}
+            
+            fallback_branch = None
+            if not has_branch(result, default_revision):
+                if os.getenv('ROOMSERVICE_BRANCHES'):
+                    fallbacks = filter(bool, os.getenv('ROOMSERVICE_BRANCHES').split(' '))
+                    for fallback in fallbacks:
+                        if has_branch(result, fallback):
+                            print "Using fallback branch: %s" % fallback
+                            fallback_branch = fallback
+                            break
+
+                if not fallback_branch:
+                    print "Default revision %s not found in %s. Bailing." % (default_revision, repo_name)
+                    print "Branches found:"
+                    for branch in [branch['name'] for branch in result]:
+                        print branch
+                    print "Use the ROOMSERVICE_BRANCHES environment variable to specify a list of fallback branches."
+                    sys.exit()
+
+            add_to_manifest([adding], fallback_branch)
+
+            print "Syncing repository to retrieve project."
+            os.system('repo sync %s' % repo_path)
+            print "Repository synced!"
+
+            fetch_dependencies(repo_path, fallback_branch)
+            print "Done"
+            sys.exit()
+
+print "Repository for %s not found in the CyanogenMod Github repository list. If this is in error, you may need to manually add it to your local_manifests/roomservice.xml." % device