diff --git a/dart/Makefile b/dart/Makefile
index 6ae7cd9..b850d95 100644
--- a/dart/Makefile
+++ b/dart/Makefile
@@ -3,10 +3,9 @@
 endif
 
 SYNCBASE_DATA_DIR=/data/data/org.chromium.mojo.shell/app_home/syncbasedata
-# Mounttable address on SyncSlides-Alpha network
-# TODO(aghassemi): Now that BLE discovery support is added and sync uses neighbourhood,
-# we should no longer need a mounttable after upgrading and testing the latest code.
-MOUNTTABLE_ADDR := /192.168.86.254:8101
+# TODO(aghassemi): We should be able to drop the mount table dependency once syncgroup creation no longer requires one.
+# See https://github.com/vanadium/issues/issues/873
+MOUNTTABLE_ADDR := /ns.dev.v.io:8101/tmp/syncslides
 
 DEVICE_NUM_PLUS_ONE := $(shell echo $(DEVICE_NUM) \+ 1 | bc)
 DEVICE_ID := $(shell adb devices | sed -n $(DEVICE_NUM_PLUS_ONE)p | awk '{ print $$1; }')
@@ -20,7 +19,8 @@
 	VLOG_FLAGS = --v=$(VLOG) --logtostderr=true
 endif
 
-SYNCBASE_ARGS := https://syncbase.syncslides.mojo.v.io/syncbase_server.mojo --root-dir=$(SYNCBASE_DATA_DIR) --v23.namespace.root=$(MOUNTTABLE_ADDR) --name=$(DEVICE_ID) $(VLOG_FLAGS)
+# TODO(aghassemi): Remove use of proxy once BLE-RPC is supported.
+SYNCBASE_ARGS := https://syncbase.syncslides.mojo.v.io/syncbase_server.mojo --root-dir=$(SYNCBASE_DATA_DIR) --v23.proxy=/ns.dev.v.io:8101/proxy --v23.namespace.root=$(MOUNTTABLE_ADDR) --name=$(DEVICE_ID) $(VLOG_FLAGS)
 
 SETTINGS_FILE := /sdcard/syncslides_settings.json
 SETTINGS_JSON := {\"deviceid\": \"$(DEVICE_ID)\", \"mounttable\": \"$(MOUNTTABLE_ADDR)\"}
diff --git a/dart/lib/stores/syncbase/actions.dart b/dart/lib/stores/syncbase/actions.dart
index 7feda01..a266586 100644
--- a/dart/lib/stores/syncbase/actions.dart
+++ b/dart/lib/stores/syncbase/actions.dart
@@ -153,7 +153,7 @@
     // Wait until at least the current slide number, driver and the slide for current slide number is synced.
     join() async {
       bool isMyOwnPresentation =
-          _state._advertisedPresentation.key == presentation.key;
+          _state._advertisedPresentation?.key == presentation.key;
       if (!isMyOwnPresentation) {
         await sb.joinSyncgroup(presentation.syncgroupName);
       }
diff --git a/dart/pubspec.lock b/dart/pubspec.lock
index af44d6f..1674050 100644
--- a/dart/pubspec.lock
+++ b/dart/pubspec.lock
@@ -238,7 +238,7 @@
   syncbase:
     description: syncbase
     source: hosted
-    version: "0.0.26"
+    version: "0.0.27"
   test:
     description: test
     source: hosted
@@ -258,7 +258,7 @@
   v23discovery:
     description: v23discovery
     source: hosted
-    version: "0.0.8"
+    version: "0.0.9"
   vector_math:
     description: vector_math
     source: hosted
diff --git a/dart/pubspec.yaml b/dart/pubspec.yaml
index 67ad8a3..f0cccde 100644
--- a/dart/pubspec.yaml
+++ b/dart/pubspec.yaml
@@ -5,8 +5,8 @@
     path: "../../../../../flutter/packages/flutter"
   logging: ">=0.11.2 <0.12.0"
   mojo_services: ">=0.4.5 <0.5.0"
-  syncbase: ">=0.0.23 <0.1.0"
-  v23discovery: ">=0.0.4 < 0.1.0"
+  syncbase: ">=0.0.27 <0.1.0"
+  v23discovery: ">=0.0.9 < 0.1.0"
   uuid: ">=0.5.0 <0.6.0"
 dev_dependencies:
   flutter_tools:
diff --git a/dart/shortcut_template b/dart/shortcut_template
index c553beb..008b5c3 100644
--- a/dart/shortcut_template
+++ b/dart/shortcut_template
@@ -1,4 +1,4 @@
---map-origin=http://flutter/=https://storage.googleapis.com/mojo/flutter/97bf8464d2c342a919a80949b7b43c403db6cf6c/android-arm/
+--map-origin=http://flutter/=https://storage.googleapis.com/mojo/flutter/90ef9fa39c36f4027b82e62262e5c0c43a0466a1/android-arm/
 --url-mappings=mojo:flutter=http://flutter/flutter.mojo
 --enable-multiprocess
 --map-origin=https://syncbase.syncslides.mojo.v.io=https://%GS_BUCKET_URL%/