diff --git a/Makefile b/Makefile
index 0bb797c6c..b2152c72e 100644
--- a/Makefile
+++ b/Makefile
@@ -87,7 +87,7 @@ crx_contents := script.js eventPage.js icon16.png icon48.png icon128.png manifes
 
 release := \
  $(foreach f, \
-  $(foreach c,. -beta.,$(name)$(c)crx updates$(c)xml $(name)$(c)user.js $(name)$(c)meta.js) \
+  $(foreach c,. -beta.,$(name)$(c)crx updates$(c)xml updates$(c)json $(name)$(c)user.js $(name)$(c)meta.js) \
   $(name)-noupdate.crx \
   $(name)-noupdate.user.js \
   $(name).zip \
@@ -184,6 +184,9 @@ testbuilds/crx$1/manifest.json : src/meta/manifest.json version.json $(template_
 testbuilds/updates$1.xml : src/meta/updates.xml version.json $(template_deps) | testbuilds/crx$1
 	$(template) $$< $$@ type=crx channel=$1
 
+testbuilds/updates$1.json : src/meta/updates.json version.json $(template_deps) | testbuilds/crx$1
+	$(template) $$< $$@ type=crx channel=$1
+
 testbuilds/$(name)$1.crx.zip : \
  $(foreach f,$(crx_contents),testbuilds/crx$1/$(f)) \
  package.json version.json tools/zip-crx.js node_modules/jszip/package.json
@@ -342,7 +345,7 @@ stable : distready
 	git push . HEAD:bstable
 	git tag -af stable -m "$(meta_name) v$(version)."
 	cd dist && git merge --no-commit -s ours stable
-	cd dist && git checkout stable "builds/$(name).*" builds/updates.xml
+	cd dist && git checkout stable "builds/$(name).*" builds/updates.xml builds/updates.json
 	cd dist && git commit -am "Move $(meta_name) v$(version) to stable channel."
 
 web : index.html distready
diff --git a/package.json b/package.json
index 1e4469f75..19efb222e 100644
--- a/package.json
+++ b/package.json
@@ -16,6 +16,7 @@
     "newIssue": "https://gitreports.com/issue/ccd0/4chan-x?issue_title=%title&details=%details",
     "newIssueMaxLength": 8181,
     "appid": "lacclbnghgdicfifcamcmcnilckjamag",
+    "appidGecko": "4chan-x@4chan-x.net",
     "chromeStoreID": "ohnjgmpcibpbafdlkimncjhflgedgpam",
     "recaptchaKey": "6Ldp2bsSAAAAAAJ5uyx_lx34lJeEpTLVkP5k04qc",
     "youtubeAPIKey": "AIzaSyB5_zaen_-46Uhz1xGR-lz1YoUMHqCD6CE",
diff --git a/src/meta/jshint.json b/src/meta/jshint.json
index 45f62a3eb..1b58dc59c 100644
--- a/src/meta/jshint.json
+++ b/src/meta/jshint.json
@@ -20,6 +20,7 @@
     "BroadcastChannel": false,
     "GM_info":      false,
     "cloneInto":    false,
+    "XPCNativeWrapper": false,
     "unsafeWindow": false,
     "chrome":       false,
     "GM":           false<%=
diff --git a/src/meta/manifest.json b/src/meta/manifest.json
index af5b31144..8438753bb 100644
--- a/src/meta/manifest.json
+++ b/src/meta/manifest.json
@@ -23,10 +23,14 @@
 <% if (channel !== '-noupdate') { %>  "update_url": "<%= meta.downloads %>updates<%= channel %>.xml",
   "key": "<%= meta.appid %>",
 <% } %>  "minimum_chrome_version": "<%= meta.min.chrome %>",
-  "permissions": [
-    "storage"
-  ],
+  "permissions": <%= JSON.stringify(meta.matches_only.concat(["storage"])) %>,
   "optional_permissions": [
     "*://*/"
-  ]
+  ],
+  "applications": {
+    "gecko": {
+      "id": "<%= meta.appidGecko %>"<% if (channel !== '-noupdate') { %>,
+      "update_url": "<%= meta.downloads %>updates<%= channel %>.json"
+<% } %>    }
+  }
 }
diff --git a/src/meta/updates.json b/src/meta/updates.json
new file mode 100644
index 000000000..dc9d876f6
--- /dev/null
+++ b/src/meta/updates.json
@@ -0,0 +1,12 @@
+{
+  "addons": {
+    "<%= meta.appidGecko %>": {
+      "updates": [
+        {
+          "version": "<%= readJSON('/version.json').version %>",
+          "update_link": "<%= meta.downloads %><%= name %><%= channel %>.crx"
+        }
+      ]
+    }
+  }
+}
diff --git a/src/platform/$.coffee b/src/platform/$.coffee
index 44c39168c..9eeaebf6d 100644
--- a/src/platform/$.coffee
+++ b/src/platform/$.coffee
@@ -45,6 +45,10 @@ $.ajax = do ->
   # With the `If-Modified-Since` header we only receive the HTTP headers and no body for 304 responses.
   # This saves a lot of bandwidth and CPU time for both the users and the servers.
   lastModified = {}
+  <% if (type === 'crx') { %>
+  if XPCNativeWrapper?
+    pageXHR = XPCNativeWrapper window.wrappedJSObject.XMLHttpRequest
+  <% } %>
 
   (url, options={}, extra={}) ->
     {type, whenModified, upCallbacks, form} = extra
@@ -53,7 +57,11 @@ $.ajax = do ->
     url = url.replace /^((?:https?:)?\/\/(?:\w+\.)?4c(?:ha|d)n\.org)\/adv\//, '$1//adv/'
     # XXX https://bugs.chromium.org/p/chromium/issues/detail?id=643659
     url += "?s=#{whenModified}" if $.engine is 'blink' and whenModified
-    r = new XMLHttpRequest()
+    xhr = XMLHttpRequest
+    <% if (type === 'crx') { %>
+    xhr = pageXHR or xhr
+    <% } %>
+    r = new xhr()
     type or= form and 'post' or 'get'
     try
       r.open type, url, true
@@ -415,9 +423,17 @@ $.get = $.oneItemSugar (data, cb) ->
   return unless $.crxWorking()
   results = {}
   get = (area) ->
-    chrome.storage[area].get Object.keys(data), (result) ->
+    keys = Object.keys data
+    # XXX slow performance in Firefox
+    if $.engine is 'gecko' and area is 'sync' and keys.length > 3
+      keys = null
+    chrome.storage[area].get keys, (result) ->
       if chrome.runtime.lastError
         c.error chrome.runtime.lastError.message
+      if keys is null
+        result2 = {}
+        result2[key] = val for key, val of result when key of data
+        result = result2
       for key of data
         $.oldValue[area][key] = result[key]
       results[area] = result