# Substitute-urls in system config (for firefox installation and upgrading)

**URL:** <https://forum.systemcrafters.net/t/substitute-urls-in-system-config-for-firefox-installation-and-upgrading/1500>\
**Category:** Guix\
**Created:** [March 19, 2025, 3:50pm UTC](https://forum.systemcrafters.net/t/substitute-urls-in-system-config-for-firefox-installation-and-upgrading/1500 "2025-03-19T15:50:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![juanpamf](https://yyz1.discourse-cdn.com/flex029/user_avatar/forum.systemcrafters.net/juanpamf/32/197_2.png) [@juanpamf](https://forum.systemcrafters.net/u/juanpamf)\
**Post date:** [March 19, 2025, 3:50pm UTC](https://forum.systemcrafters.net/t/substitute-urls-in-system-config-for-firefox-installation-and-upgrading/1500/1 "2025-03-19T15:50:48Z")

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Hi,

I had some trouble installing firefox without having to build it locally until I found this futurile blog post:

> **[Installing Chrome and other proprietary apps on Guix](https://www.futurile.net/2022/12/04/proprietary-apps-on-guix-using-nonguix-channel/)**

I am trying now to add this to my system config so whenever I upgrade (or port my config) I don’t need to add manually the substitute urls to the guix command.

Still a noob with Guile so asking for help on how should I add this to my conf.

---

<div class="post-metadata">

**Author:** ![Trisk3lion](https://avatars.discourse-cdn.com/v4/letter/t/9e8a1a/32.png) [@Trisk3lion](https://forum.systemcrafters.net/u/Trisk3lion)\
**Post date:** [March 22, 2025, 6:35am UTC](https://forum.systemcrafters.net/t/substitute-urls-in-system-config-for-firefox-installation-and-upgrading/1500/2 "2025-03-22T06:35:46Z")

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Here is how I do it:

```auto
(define %nonguix-key
  (plain-file
   "nonguix-archive-key.pub"
   "(public-key
    (ecc
     (curve Ed25519)
     (q #C1FD53E5D4CE971933EC50C9F307AE2171A2D3B52C804642A7A35F84F3A4EA98#)))"))

(operating system
....
(services
   (append
       (modify-services %desktop-services
            (guix-service-type config =>
                              (guix-configuration
                              (inherit config)
                              (authorize-key? #f)
                              (discover? #t)
                              (authorized-keys
                               (append (list %nonguix-key)
                                             %default-authorized-guix-keys))
                              (substitute-urls
                              (append (list "https://substitutes.nonguix.org")
                                            %default-substitute-urls)))))
....
)
```