--- a/mozilla/config.py
+++ b/mozilla/config.py
@@ -2584,16 +2584,25 @@ for name, branch in BRANCHES.items():
                 pf = branch['platforms'][platform_name]
                 pf['desktop_mozharness_repacks_enabled'] = True
         continue
     # for all other branches delete mozharness_desktop_l10n
     for p in branch["platforms"]:
         if "mozharness_desktop_l10n" in p:
             del p["mozharness_desktop_l10n"]
 
+# enable mozharness desktop builds across all twigs
+for name, branch in items_at_least(BRANCHES, 'gecko_version', mc_gecko_version):
+    if name in ('mozilla-central', 'mozilla-inbound', 'b2g-inbound', 'try'):
+        # only enable on twigs for now
+        continue
+    # if true, any platform with mozharness_desktop_build in its config
+    # will use mozharness instead of MozillaBuildFactory
+    branch['desktop_mozharness_builds_enabled'] = True
+
 # Bug 950206 - Enable 32-bit Windows builds on Date, test those builds on tst-w64-ec2-XXXX
 BRANCHES['date']['platforms']['win32']['unittest_platform'] = 'win64-opt'
 
 if __name__ == "__main__":
     import sys
     import pprint
     args = sys.argv[1:]
 

--- a/mozilla/project_branches.py
+++ b/mozilla/project_branches.py
@@ -116,45 +116,36 @@ PROJECT_BRANCHES = {
         'mobile_platforms': {
             'android': {
                 'slave_platforms': ['panda_android', 'ubuntu64_vm_large'],
             },
             'android-x86': {
                 'enable_opt_unittests': True,
             },
         },
-        # if true, any platform with mozharness_desktop_build in its config
-        # will use mozharness instead of MozharnessBuildFactory
-        'desktop_mozharness_builds_enabled': True,
     },
     #'birch': {},  # Bug 1010674
     'cedar': {
         'enable_perproduct_builds': False,
         'mozharness_tag': 'default',
         'enable_talos': True,
         'talos_suites': {
             'xperf': 1,
         },
         'enable_opt_unittests': True,
         'mobile_platforms': {
             'android-x86': {
                 'enable_opt_unittests': True,
             },
         },
-        # if true, any platform with mozharness_desktop_build in its config
-        # will use mozharness instead of MozharnessBuildFactory
-        'desktop_mozharness_builds_enabled': True,
     },
     'cypress': {
         'enable_perproduct_builds': False,
         'mozharness_tag': 'default',
         'enable_talos': True,
-        # if true, any platform with mozharness_desktop_build in its config
-        # will use mozharness instead of MozharnessBuildFactory
-        'desktop_mozharness_builds_enabled': True,
     },
     'date': {
         'lock_platforms': True,
         'platforms': {
             'win32': {
                 'enable_opt_unittests': True,
                 'slave_platforms': ['xp-ix', 'win7-ix'],
                 'talos_slave_platforms': ['xp-ix', 'win7-ix'],