Is your Android mobile FULL? Backup your data to your Arch Linux. It is easy following my steps (I hope hahaha). I had some trouble with other programs (android-file-transfer e mtpfs), so here it goes what works for me:
If you do not have or know what is Yaourt, please check it out: https://angeloocana.com/en/blog/linux/arch/install-yaourt/
yaourt -S simple-mtpfs
Create destination folder
I’ll be using mnt folder, you can use any name, but remember it for the next step.
Mount your Phone to a folder
simple-mtpfs --device 1 ~/mnt
That is it! uhuhuh Just go to ~/mnt, your files will be there!
Official guide: https://wiki.archlinux.org/index.php/MTP