The following is a very old solution but still works. So please check this out.

By default, Firefox for Android will use the Android Downloads folder as its default download location. You can change this as follows.

Changing the download location on Firefox for Android requires a visit to the about:config preferences editor. You have to change two different settings to make this work.

First, you need to know the folder path you want to use. An app like ES File Explorer File Manager will be helpful if you do not have a file manager.

(1) Open a new tab to about:config (type about:config in the Awesomebar and tap the go arrow or tap Enter).

You may want to bookmark this for easier future access.

(2) In the search box, type down and tap Enter

(3) Scroll down to browser.download.folderList and tap Modify, then change the value from 1 to 2 (from "default always" to "last used folder"). The change should appear after a few seconds.

(3) Scroll back up and tap the large "+" button to the left of the search box to add a new setting

(A) The name of the preference should be browser.download.dir (this stores the last used directory)

(B) On the right side, tap Boolean and in the popup change it to String

(C) The value depends on the folder you want. For example:

/sdcard/FxDown

(D) Then click Create (if you are too slow, it may clear and you might have to start again)

If you switch back to your other tab and download something, it should go to the new folder.

Hi, Thank you, rajath4554. Your explanation is clear, this is the 'solution' I've been exploring for a few weeks. The (C) point (value depending on the folder I want) is exactly my issue. No values I've tried yet led to a correct behavior. /sdcard/Download /storage/1140-xxxx/Download (path indicated by Mix Explorer) /mnt/media_rw/1140-xxxx/Download (other exploring app) /mnt/sdcard/download

By the way, I've also tried an old 'solution' (installing ES File Explorer, a parameter in the options allows to change the defaut Download Folder on Android) => inefficient in Android 10.

I currently wonder why we can't simply let the folder parameter blank in about:config, in order to let Firefox ask us the right path once and for all?

I've explored randomly a lot of other paths, no success. Sometimes the download doesn't start, sometimes it plainly goes to the internal storage path. No other behaviour. I'm asking myself if it's not a permission issue, the internal folder being 770 (rwx rwx ---) and the external one 755 (rwx r-x r-x). Of course Android doesn't let me change the values...

Btw I've tried the Samsung Internet app, you can change (Parameters>Sites and Download>Download files on...) between internal and sdcard folder... I've checked, it all works.