Yes, you can use Firefox for commercial use.

This is incorrect, see my reply. [edited kbrosnan]

TyDraniu does not represent Mozilla when it comes to licensing. We are not able to grant you a license in this forum.

If you want to use a completely unmodified version of Firefox that may be possible. If you want to modify Firefox in any way or recompile and want to call the app Firefox you must get an agreement from Mozilla by contacting licensing@mozilla.org.

See https://www.mozilla.org/en-US/foundation/licensing/

Thank you for answers.

hmm...

I do not know much about Mozilla licensing.

I will just install and use the current distribution version on the set-top box (tv receiver) without modifying the Firefox source.

Do I need a license agreement with Mozilla in this case?

I am not a lawyer and cannot represent Mozilla in this matter. You need to reach out to licensing@mozilla.org

Hi JeongMinKim, as you probably know, Mozilla issues Firefox security updates quite often. Those would be easier to manage if your set-top box customers install using the Google Play store app, if that is an option. Otherwise, if you cannot ensure that those are installed promptly, you create the potential for customers having a vulnerable browser that provides an attacker access to your platform.