diff --git a/browser/base/content/aboutaccounts/aboutaccounts.js b/browser/base/content/aboutaccounts/aboutaccounts.js
index c98c0ae941a..e009af9fe4c 100644
--- a/browser/base/content/aboutaccounts/aboutaccounts.js
+++ b/browser/base/content/aboutaccounts/aboutaccounts.js
@@ -16,7 +16,7 @@ Cu.import("resource://gre/modules/FxAccountsCommon.js", fxAccountsCommon);
 Cu.import("resource://services-sync/util.js");
 
 const PREF_LAST_FXA_USER = "identity.fxaccounts.lastSignedInUserHash";
-const PREF_SYNC_SHOW_CUSTOMIZATION = "services.sync.ui.showCustomizationDialog";
+const PREF_SYNC_SHOW_CUSTOMIZATION = "services.sync-setup.ui.showCustomizationDialog";
 
 const ACTION_URL_PARAM = "action";
 
diff --git a/services/sync/modules/FxaMigrator.jsm b/services/sync/modules/FxaMigrator.jsm
index 1027b15afb2..737ff36ab2d 100644
--- a/services/sync/modules/FxaMigrator.jsm
+++ b/services/sync/modules/FxaMigrator.jsm
@@ -210,27 +210,39 @@ Migrator.prototype = {
 
     // Must be ready to perform the actual migration.
     this.log.info("Performing final sync migration steps");
-    // Do the actual migration.
+    // Do the actual migration.  We setup one observer for when the new identity
+    // is about to be initialized so we can reset some key preferences - but
+    // there's no promise associated with this.
+    let observeStartOverIdentity;
+    Services.obs.addObserver(observeStartOverIdentity = () => {
+      this.log.info("observed that startOver is about to re-initialize the identity");
+      Services.obs.removeObserver(observeStartOverIdentity, "weave:service:start-over:init-identity");
+      // We've now reset all sync prefs - set the engine related prefs back to
+      // what they were.
+      for (let [prefName, prefType, prefVal] of enginePrefs) {
+        this.log.debug("Restoring pref ${prefName} (type=${prefType}) to ${prefVal}",
+                       {prefName, prefType, prefVal});
+        switch (prefType) {
+          case Services.prefs.PREF_BOOL:
+            Services.prefs.setBoolPref(prefName, prefVal);
+            break;
+          case Services.prefs.PREF_STRING:
+            Services.prefs.setCharPref(prefName, prefVal);
+            break;
+          default:
+            // _getEngineEnabledPrefs doesn't return any other type...
+            Cu.reportError("unknown engine pref type for " + prefName + ": " + prefType);
+        }
+      }
+    }, "weave:service:start-over:init-identity", false);
+
+    // And another observer for the startOver being fully complete - the only
+    // reason for this is so we can wait until everything is fully reset.
     let startOverComplete = new Promise((resolve, reject) => {
       let observe;
       Services.obs.addObserver(observe = () => {
         this.log.info("observed that startOver is complete");
         Services.obs.removeObserver(observe, "weave:service:start-over:finish");
-        // We've now reset all sync prefs - set the engine related prefs back to
-        // what they were.
-        for (let [prefName, prefType, prefVal] of enginePrefs) {
-          switch (prefType) {
-            case Services.prefs.PREF_BOOL:
-              Services.prefs.setBoolPref(prefName, prefVal);
-              break;
-            case Services.prefs.PREF_STRING:
-              Services.prefs.setCharPref(prefName, prefVal);
-              break;
-            default:
-              // _getEngineEnabledPrefs doesn't return any other type...
-              Cu.reportError("unknown engine pref type for " + prefName + ": " + prefType);
-          }
-        }
         resolve();
       }, "weave:service:start-over:finish", false);
     });
@@ -240,6 +252,8 @@ Migrator.prototype = {
     yield startOverComplete;
     // observer fired, now kick things off with the FxA user.
     this.log.info("scheduling initial FxA sync.");
+    // Note we technically don't need to unblockSync as by now all sync prefs
+    // have been reset - but it doesn't hurt.
     this._unblockSync();
     Weave.Service.scheduler.scheduleNextSync(0);
 
diff --git a/services/sync/modules/browserid_identity.js b/services/sync/modules/browserid_identity.js
index ef8d737d22c..f466c386e90 100644
--- a/services/sync/modules/browserid_identity.js
+++ b/services/sync/modules/browserid_identity.js
@@ -47,7 +47,7 @@ const OBSERVER_TOPICS = [
   fxAccountsCommon.ONLOGOUT_NOTIFICATION,
 ];
 
-const PREF_SYNC_SHOW_CUSTOMIZATION = "services.sync.ui.showCustomizationDialog";
+const PREF_SYNC_SHOW_CUSTOMIZATION = "services.sync-setup.ui.showCustomizationDialog";
 
 function deriveKeyBundle(kB) {
   let out = CryptoUtils.hkdf(kB, undefined,
diff --git a/services/sync/modules/policies.js b/services/sync/modules/policies.js
index 80992e7eb1f..4451ca79d98 100644
--- a/services/sync/modules/policies.js
+++ b/services/sync/modules/policies.js
@@ -592,8 +592,10 @@ ErrorHandler.prototype = {
     fapp.level = Log.Level[Svc.Prefs.get("log.appender.file.level")];
     root.addAppender(fapp);
 
-    // Arrange for the FxA, Hawk and TokenServer logs to also go to our appenders.
-    for (let extra of ["FirefoxAccounts", "Hawk", "Common.TokenServerClient"]) {
+    // Arrange for a number of other sync-related logs to also go to our
+    // appenders.
+    for (let extra of ["FirefoxAccounts", "Hawk", "Common.TokenServerClient",
+                       "Sync.SyncMigration"]) {
       let log = Log.repository.getLogger(extra);
       for (let appender of [fapp, dapp, capp]) {
         log.addAppender(appender);
diff --git a/services/sync/modules/service.js b/services/sync/modules/service.js
index 88b68505f7d..22cd713148d 100644
--- a/services/sync/modules/service.js
+++ b/services/sync/modules/service.js
@@ -926,6 +926,9 @@ Sync11Service.prototype = {
 
     this.identity.finalize().then(
       () => {
+        // an observer so the FxA migration code can take some action before
+        // the new identity is created.
+        Svc.Obs.notify("weave:service:start-over:init-identity");
         this.identity.username = "";
         this.status.__authManager = null;
         this.identity = Status._authManager;