diff --git a/src/cards/ha-camera-card.js b/src/cards/ha-camera-card.js
index c26eedf563..575a5a3613 100644
--- a/src/cards/ha-camera-card.js
+++ b/src/cards/ha-camera-card.js
@@ -99,20 +99,19 @@ class HaCameraCard extends LocalizeMixin(EventsMixin(PolymerElement)) {
     this.fire('hass-more-info', { entityId: this.stateObj.entity_id });
   }
 
-  updateCameraFeedSrc() {
-    this.hass.connection.sendMessagePromise({
-      type: 'camera_thumbnail',
-      entity_id: this.stateObj.entity_id,
-    }).then((resp) => {
-      if (resp.success) {
-        this.setProperties({
-          imageLoaded: true,
-          cameraFeedSrc: `data:${resp.result.content_type};base64, ${resp.result.content}`,
-        });
-      } else {
-        this.imageLoaded = false;
-      }
-    });
+  async updateCameraFeedSrc() {
+    try {
+      const { content_type: contentType, content } = await this.hass.callWS({
+        type: 'camera_thumbnail',
+        entity_id: this.stateObj.entity_id,
+      });
+      this.setProperties({
+        imageLoaded: true,
+        cameraFeedSrc: `data:${contentType};base64, ${content}`,
+      });
+    } catch (err) {
+      this.imageLoaded = false;
+    }
   }
 
   _computeStateName(stateObj) {
diff --git a/src/cards/ha-media_player-card.js b/src/cards/ha-media_player-card.js
index cce9491067..d5e3ae1dfc 100644
--- a/src/cards/ha-media_player-card.js
+++ b/src/cards/ha-media_player-card.js
@@ -200,27 +200,7 @@ class HaMediaPlayerCard extends LocalizeMixin(EventsMixin(PolymerElement)) {
     };
   }
 
-  playerObjChanged(playerObj, oldPlayerObj) {
-    const picture = playerObj.stateObj.attributes.entity_picture;
-    const oldPicture = oldPlayerObj && oldPlayerObj.stateObj.attributes.entity_picture;
-
-    if (picture !== oldPicture && !picture) {
-      this.$.cover.style.backgroundImage = '';
-    } else if (picture !== oldPicture) {
-      // We have a new picture url
-      this.hass.connection.sendMessagePromise({
-        type: 'media_player_thumbnail',
-        entity_id: playerObj.stateObj.entity_id,
-      }).then((resp) => {
-        if (resp.success) {
-          this.$.cover.style.backgroundImage = `url(data:${resp.result.content_type};base64,${resp.result.content})`;
-        } else {
-          this.$.cover.style.backgroundImage = '';
-          this.$.cover.parentElement.classList.add('no-cover');
-        }
-      });
-    }
-
+  async playerObjChanged(playerObj, oldPlayerObj) {
     if (playerObj.isPlaying && playerObj.showProgress) {
       if (!this._positionTracking) {
         this._positionTracking = setInterval(() => this.updatePlaybackPosition(), 1000);
@@ -232,6 +212,28 @@ class HaMediaPlayerCard extends LocalizeMixin(EventsMixin(PolymerElement)) {
     if (playerObj.showProgress) {
       this.updatePlaybackPosition();
     }
+
+    const picture = playerObj.stateObj.attributes.entity_picture;
+    const oldPicture = oldPlayerObj && oldPlayerObj.stateObj.attributes.entity_picture;
+
+    if (picture !== oldPicture && !picture) {
+      this.$.cover.style.backgroundImage = '';
+      return;
+    } else if (picture === oldPicture) {
+      return;
+    }
+
+    // We have a new picture url
+    try {
+      const { content_type: contentType, content } = await this.hass.callWS({
+        type: 'media_player_thumbnail',
+        entity_id: playerObj.stateObj.entity_id,
+      });
+      this.$.cover.style.backgroundImage = `url(data:${contentType};base64,${content})`;
+    } catch (err) {
+      this.$.cover.style.backgroundImage = '';
+      this.$.cover.parentElement.classList.add('no-cover');
+    }
   }
 
   updatePlaybackPosition() {
diff --git a/src/dialogs/ha-more-info-dialog.js b/src/dialogs/ha-more-info-dialog.js
index 163c654842..ad21496726 100644
--- a/src/dialogs/ha-more-info-dialog.js
+++ b/src/dialogs/ha-more-info-dialog.js
@@ -128,7 +128,7 @@ class HaMoreInfoDialog extends DialogMixin(PolymerElement) {
     return hass.states[hass.moreInfoEntityId] || null;
   }
 
-  _stateObjChanged(newVal, oldVal) {
+  async _stateObjChanged(newVal, oldVal) {
     if (!newVal) {
       this.setProperties({
         opened: false,
@@ -139,22 +139,26 @@ class HaMoreInfoDialog extends DialogMixin(PolymerElement) {
       return;
     }
 
-    if (isComponentLoaded(this.hass, 'config.entity_registry') &&
-        (!oldVal || oldVal.entity_id !== newVal.entity_id)) {
-      this.hass.connection.sendMessagePromise({
-        type: 'config/entity_registry/get',
-        entity_id: newVal.entity_id,
-      }).then(
-        (msg) => { this._registryInfo = msg.result; },
-        () => { this._registryInfo = false; }
-      );
-    }
-
     requestAnimationFrame(() => requestAnimationFrame(() => {
       // allow dialog to render content before showing it so it will be
       // positioned correctly.
       this.opened = true;
     }));
+
+    if (!isComponentLoaded(this.hass, 'config.entity_registry') ||
+        (oldVal && oldVal.entity_id === newVal.entity_id)) {
+      return;
+    }
+
+    try {
+      const info = await this.hass.callWS({
+        type: 'config/entity_registry/get',
+        entity_id: newVal.entity_id,
+      });
+      this._registryInfo = info;
+    } catch (err) {
+      this._registryInfo = null;
+    }
   }
 
   _dialogOpenChanged(newVal) {
diff --git a/src/dialogs/more-info/more-info-settings.js b/src/dialogs/more-info/more-info-settings.js
index 85b5e63c27..7e3f448ffd 100644
--- a/src/dialogs/more-info/more-info-settings.js
+++ b/src/dialogs/more-info/more-info-settings.js
@@ -94,15 +94,17 @@ class MoreInfoSettings extends LocalizeMixin(EventsMixin(PolymerElement)) {
     this.fire('more-info-page', { page: null });
   }
 
-  _save() {
-    this.hass.connection.sendMessagePromise({
-      type: 'config/entity_registry/update',
-      entity_id: this.stateObj.entity_id,
-      name: this._name,
-    }).then(
-      (msg) => { this.registryInfo = msg.result; },
-      () => { alert('save failed!'); }
-    );
+  async _save() {
+    try {
+      const info = await this.hass.callWS({
+        type: 'config/entity_registry/update',
+        entity_id: this.stateObj.entity_id,
+        name: this._name,
+      });
+      this.registryInfo = info;
+    } catch (err) {
+      alert('save failed!');
+    }
   }
 }
 customElements.define('more-info-settings', MoreInfoSettings);
diff --git a/src/entrypoints/app.js b/src/entrypoints/app.js
index 2ac312c825..6e13be822a 100644
--- a/src/entrypoints/app.js
+++ b/src/entrypoints/app.js
@@ -132,7 +132,7 @@ class HomeAssistant extends LocalizeMixin(PolymerElement) {
 
     const language = this.hass.selectedLanguage || this.hass.language;
 
-    const resp = await this.hass.connection.sendMessagePromise({
+    const { resources } = await this.hass.callWS({
       type: 'frontend/get_translations',
       language,
     });
@@ -140,7 +140,7 @@ class HomeAssistant extends LocalizeMixin(PolymerElement) {
     // If we've switched selected languages just ignore this response
     if ((this.hass.selectedLanguage || this.hass.language) !== language) return;
 
-    this._updateResources(language, resp.result.resources);
+    this._updateResources(language, resources);
   }
 
   _updateResources(language, data) {
@@ -427,10 +427,10 @@ class HomeAssistant extends LocalizeMixin(PolymerElement) {
   }
 
   async _loadPanels() {
-    const msg = await this.connection.sendMessagePromise({
+    const panels = await this.hass.callWS({
       type: 'get_panels'
     });
-    this._updateHass({ panels: msg.result });
+    this._updateHass({ panels });
   }
 
 
diff --git a/src/panels/lovelace/components/hui-image.js b/src/panels/lovelace/components/hui-image.js
index 5ec4d1accd..e205a711e3 100644
--- a/src/panels/lovelace/components/hui-image.js
+++ b/src/panels/lovelace/components/hui-image.js
@@ -135,18 +135,17 @@ class HuiImage extends LocalizeMixin(PolymerElement) {
     this.$.image.style.filter = filter || (isOff && this._imageFallback && DEFAULT_FILTER) || '';
   }
 
-  _updateCameraImageSrc() {
-    this.hass.connection.sendMessagePromise({
-      type: 'camera_thumbnail',
-      entity_id: this.cameraImage,
-    }).then((resp) => {
-      if (resp.success) {
-        this._imageSrc = `data:${resp.result.content_type};base64, ${resp.result.content}`;
-        this._onImageLoad();
-      } else {
-        this._onImageError();
-      }
-    }, () => this._onImageError());
+  async _updateCameraImageSrc() {
+    try {
+      const { content_type: contentType, content } = await this.hass.callWS({
+        type: 'camera_thumbnail',
+        entity_id: this.cameraImage,
+      });
+      this._imageSrc = `data:${contentType};base64, ${content}`;
+      this._onImageLoad();
+    } catch (err) {
+      this._onImageError();
+    }
   }
 }
 
diff --git a/src/panels/lovelace/ha-panel-lovelace.js b/src/panels/lovelace/ha-panel-lovelace.js
index a023e92856..c8d10600e2 100644
--- a/src/panels/lovelace/ha-panel-lovelace.js
+++ b/src/panels/lovelace/ha-panel-lovelace.js
@@ -102,18 +102,19 @@ class Lovelace extends PolymerElement {
     this._columns = Math.max(1, matchColumns - (!this.narrow && this.showMenu));
   }
 
-  _fetchConfig() {
-    this.hass.connection.sendMessagePromise({ type: 'frontend/lovelace_config' })
-      .then(
-        conf => this.setProperties({
-          _config: conf.result,
-          _state: 'loaded',
-        }),
-        err => this.setProperties({
-          _state: 'error',
-          _errorMsg: err.message,
-        })
-      );
+  async _fetchConfig() {
+    try {
+      const conf = await this.hass.callWS({ type: 'frontend/lovelace_config' });
+      this.setProperties({
+        _config: conf,
+        _state: 'loaded',
+      });
+    } catch (err) {
+      this.setProperties({
+        _state: 'error',
+        _errorMsg: err.message,
+      });
+    }
   }
 
   _equal(a, b) {