Manual installation of the security certificate into the Firefox browser

Different versions of Firefox require different approaches for AdGuard to perform HTTPS filtering.
If you can't install the certificate directly into the browser itself (most of the time this happens in v79.0 or newer, but we are hoping Mozilla might fix this in upcoming versions), try method 1 described below. If that doesn't work too, try method 2 — it takes up some time but should work for any Firefox version.

Enabling access to certificates installed on device

Method 1 (Certificate located in the User store)

To make Firefox (and browsers based on it) trust user certificates, you need to toggle the hidden option in the browser itself.

  1. Run Firefox;
  2. Navigate to about:config page;
  3. Type root in the search field;
  4. Locate the option “security.enterprise_roots.enabled” and toggle it, making it true.

Method 2 (Certificate located in the System store)

  1. Install and configure adb;

    On the Windows platform, Samsung owners may need to install this utility.

  2. Activate the developer mode and enable USB debugging:
    • Open the Settings application on your phone;
    • Go to System section (last item in the settings menu). In this section find sub-item About phone;
    • Click on the Build number line 7 times. After that, you will receive a notification that You are now a developer (If necessary, enter an unlock code for the device);
    • Open System Settings > Developer Options > Scroll down and enable USB debugging > Confirm debugging is enabled in the window Allow USB debbuging after reading the warning carefully.
  3. Install the Firefox browser (release version);
  4. Open the AdGuard settings > Network > HTTPS Filtering > Install the certificate in Firefox > INSTALL FOR OLD VERSIONS;
  5. Open the folder data/data/org.mozilla.firefox/files/mozilla using adb shell su and cd data/data/..., then browse to the folder named xxxxxxx.default and memorize its name;
  6. In the specified folder we are interested in two files:
    • cert9.db
    • key4.db
  7. We need to move these files to a folder of the browser where the security certificate issue occurred:
    • data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyy.default.
  8. The full сommand will look like this:
    • adb shell su
    • cp -R data/data/org.mozilla.firefox/files/mozilla/xxxxxxxxxx.default/cert9.db data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyyyyyy.default.
    • cp -R data/data/org.mozilla.firefox/files/mozilla/xxxxxxxxxx.default/key4.db data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyyyyyy.default.

In case you received the system notification permission denied, you should first move the specified files to the permission-free directory. And after that you should move them to the necessary folder in your Firefox browser.
The full command should look something like this:

  • adb shell su.
  • cp -R data/data/org.mozilla.firefox/files/mozilla/xxxxxxxx.default/cert9.db sdcard/Download
  • cp -R data/data/org.mozilla.firefox/files/mozilla/xxxxxxxxx.default/key4.db sdcard/Download
  • cp -R sdcard/Download/cert9.db data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyyyyyy.default.
  • cp -R sdcard/Download/key4.db data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyyyyyy.default.
    If adb shell su does not work, you should try adb shell initially, and then su.