diff --git a/src/core/index.js b/src/core/index.js
index 214de522..61945740 100644
--- a/src/core/index.js
+++ b/src/core/index.js
@@ -68,22 +68,24 @@ module.exports = function SwaggerUI(opts) {
   var system = store.getSystem()
   let queryConfig = parseSeach()
 
-  const downloadSpec = () => {
+  const downloadSpec = (fetchedConfig) => {
     if(typeof constructorConfig !== "object") {
       return system
     }
 
     let localConfig = system.specSelectors.getLocalConfig ? system.specSelectors.getLocalConfig() : {}
-    let mergedConfig = deepExtend({}, constructorConfig, localConfig, queryConfig)
+    let mergedConfig = deepExtend({}, constructorConfig, localConfig, fetchedConfig || {}, queryConfig)
     store.setConfigs(filterConfigs(mergedConfig))
 
-    if(!queryConfig.url && typeof mergedConfig.spec === "object" && Object.keys(mergedConfig.spec).length) {
-      system.specActions.updateUrl("")
-      system.specActions.updateLoadingStatus("success")
-      system.specActions.updateSpec(JSON.stringify(mergedConfig.spec))
-    } else if(system.specActions.download && mergedConfig.url) {
-      system.specActions.updateUrl(mergedConfig.url)
-      system.specActions.download(mergedConfig.url)
+    if (fetchedConfig !== null) {
+      if (!queryConfig.url && typeof mergedConfig.spec === "object" && Object.keys(mergedConfig.spec).length) {
+        system.specActions.updateUrl("")
+        system.specActions.updateLoadingStatus("success")
+        system.specActions.updateSpec(JSON.stringify(mergedConfig.spec))
+      } else if (system.specActions.download && mergedConfig.url) {
+        system.specActions.updateUrl(mergedConfig.url)
+        system.specActions.download(mergedConfig.url)
+      }
     }
 
     if(mergedConfig.dom_id) {
@@ -95,7 +97,9 @@ module.exports = function SwaggerUI(opts) {
     return system
   }
 
-  if (!system.specActions.getConfigByUrl || (system.specActions.getConfigByUrl && !system.specActions.getConfigByUrl(downloadSpec))) {
+  let configUrl = queryConfig.config || constructorConfig.configUrl
+
+  if (!configUrl || !system.specActions.getConfigByUrl || system.specActions.getConfigByUrl && !system.specActions.getConfigByUrl(configUrl, downloadSpec)) {
     return downloadSpec()
   }
 
diff --git a/src/plugins/configs/index.js b/src/plugins/configs/index.js
index 51317fc6..a3560be1 100644
--- a/src/plugins/configs/index.js
+++ b/src/plugins/configs/index.js
@@ -1,5 +1,4 @@
 import YAML from "js-yaml"
-import { parseSeach } from "core/utils"
 import yamlConfig from "../../../swagger-config.yaml"
 
 const CONFIGS = [ "url", "spec", "validatorUrl", "onComplete", "onFailure", "authorizations", "docExpansion",
@@ -27,9 +26,7 @@ export default function configPlugin (toolbox) {
             return fetch(url)
         },
 
-        getConfigByUrl: (callback)=> ({ specActions }) => {
-            let config = parseSeach()
-            let configUrl = config.config
+        getConfigByUrl: (configUrl, cb)=> ({ specActions }) => {
             if (configUrl) {
                 return specActions.downloadConfig(configUrl).then(next, next)
             }
@@ -37,9 +34,12 @@ export default function configPlugin (toolbox) {
             function next(res) {
                 if (res instanceof Error || res.status >= 400) {
                     specActions.updateLoadingStatus("failedConfig")
+                    specActions.updateLoadingStatus("failedConfig")
+                    specActions.updateUrl("")
                     console.error(res.statusText + " " + configUrl)
+                    cb(null)
                 } else {
-                    callback(parseYamlConfig(res.text))
+                    cb(parseYamlConfig(res.text))
                 }
             }
         }