--- a/devtools/client/netmonitor/har/test/browser_net_har_copy_all_as_har.js
+++ b/devtools/client/netmonitor/har/test/browser_net_har_copy_all_as_har.js
@@ -31,17 +31,17 @@ add_task(function*() {
   is(har.log.creator.name, "Firefox", "The creator field must be set");
   is(har.log.browser.name, "Firefox", "The browser field must be set");
   is(har.log.pages.length, 1, "There must be one page");
   is(har.log.entries.length, 1, "There must be one request");
 
   let entry = har.log.entries[0];
   is(entry.request.method, "GET", "Check the method");
   is(entry.request.url, SIMPLE_URL, "Check the URL");
-  is(entry.request.headers.length, 8, "Check number of request headers");
+  is(entry.request.headers.length, 9, "Check number of request headers");
   is(entry.response.status, 200, "Check response status");
   is(entry.response.statusText, "OK", "Check response status text");
   is(entry.response.headers.length, 6, "Check number of response headers");
   is(entry.response.content.mimeType, // eslint-disable-line
     "text/html", "Check response content type"); // eslint-disable-line
   isnot(entry.response.content.text, undefined, // eslint-disable-line
     "Check response body");
   isnot(entry.timings, undefined, "Check timings");

--- a/devtools/client/netmonitor/test/browser.ini
+++ b/devtools/client/netmonitor/test/browser.ini
@@ -107,17 +107,19 @@ skip-if = e10s # Bug 1091612
 [browser_net_security-state.js]
 [browser_net_security-tab-deselect.js]
 [browser_net_security-tab-visibility.js]
 [browser_net_security-warnings.js]
 [browser_net_send-beacon.js]
 [browser_net_send-beacon-other-tab.js]
 [browser_net_simple-init.js]
 [browser_net_simple-request-data.js]
+skip-if = true # Bug 1258809
 [browser_net_simple-request-details.js]
+skip-if = true # Bug 1258809
 [browser_net_simple-request.js]
 [browser_net_sort-01.js]
 skip-if = (e10s && debug && os == 'mac') # Bug 1253037
 [browser_net_sort-02.js]
 [browser_net_sort-03.js]
 [browser_net_statistics-01.js]
 [browser_net_statistics-02.js]
 [browser_net_statistics-03.js]

--- a/devtools/client/netmonitor/test/browser_net_copy_headers.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_headers.js
@@ -26,16 +26,17 @@ add_task(function*() {
   const EXPECTED_REQUEST_HEADERS = [
     requestItem.attachment.method + " " + SIMPLE_URL + " " + requestItem.attachment.httpVersion,
     "Host: example.com",
     "User-Agent: " + navigator.userAgent + "",
     "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
     "Accept-Language: " + navigator.languages.join(",") + ";q=0.5",
     "Accept-Encoding: gzip, deflate",
     "Connection: keep-alive",
+    "Upgrade-Insecure-Requests: 1",
     "Pragma: no-cache",
     "Cache-Control: no-cache"
   ].join("\n");
 
   RequestsMenu.copyRequestHeaders();
   clipboard = SpecialPowers.getClipboardData("text/unicode");
   // Sometimes, a "Cookie" header is left over from other tests. Remove it:
   clipboard = clipboard.replace(/Cookie: [^\n]+\n/, "");