[Xiaomi Mi Pad 5 Pro] chr0nic_flashr:
I've tried that and it defaults to snap and fails. Went through all of the methods here, except for using a package manager and direct download and they all fail: https://support.mozilla.org/en-US/k...your-distribution-package-manager-recommended.

root@xiaomi-elish:/# sudo apt-get update
Hit:1 https://cli.github.com/packages stable InRelease
Hit:3 http://mirrors.jevincanders.net/armbian/apt jammy InRelease
Hit:2 https://packages.microsoft.com/repos/code stable InRelease
Hit:4 http://ports.ubuntu.com jammy InRelease
Hit:5 http://ports.ubuntu.com jammy-security InRelease
Hit:6 http://ports.ubuntu.com jammy-updates InRelease
Hit:7 http://ppa.launchpad.net/ubuntu-mozilla-security/ppa/ubuntu jammy InRelease
Get:8 http://archive.neon.kde.org/testing jammy InRelease [194 kB]
Hit:9 http://ports.ubuntu.com jammy-backports InRelease
Hit:10 https://ppa.launchpadcontent.net/liujianfeng1994/chromium/ubuntu jammy InRelease
Hit:11 https://ppa.launchpadcontent.net/liujianfeng1994/qcom-mainline/ubuntu jammy InRelease
Hit:12 https://ppa.launchpadcontent.net/mozillateam/ppa/ubuntu jammy InRelease
Fetched 194 kB in 3s (77.1 kB/s)
Reading package lists... Done
root@xiaomi-elish:/# apt-get install firefox
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
firefox
0 upgraded, 1 newly installed, 0 to remove and 15 not upgraded.
Need to get 72.4 kB of archives.
After this operation, 261 kB of additional disk space will be used.
Get:1 http://ppa.launchpad.net/ubuntu-mozilla-security/ppa/ubuntu jammy/main arm64 firefox arm64 1:1snap1-0ubu
ntu3~22.04.1 [72.4 kB]
Fetched 72.4 kB in 0s (167 kB/s)
Preconfiguring packages ...
(Reading database ... 169061 files and directories currently installed.)
Preparing to unpack .../firefox_1%3a1snap1-0ubuntu3~22.04.1_arm64.deb ...
=> Installing the firefox snap
==> Checking connectivity with the snap store
==> Installing the firefox snap
error: cannot perform the following tasks:
- Mount snap "firefox" (4039) (systemctl command [reload-or-restart snap-firefox-4039.mount] failed with exit
status 1: stderr:
Job failed. See "journalctl -xe" for details.)
- Mount snap "gnome-42-2204" (174) (systemctl command [reload-or-restart snap-gnome\x2d42\x2d2204-174.mount] f
ailed with exit status 1: stderr:
Job failed. See "journalctl -xe" for details.)
- Mount snap "gtk-common-themes" (1535) (systemctl command [reload-or-restart snap-gtk\x2dcommon\x2dthemes-153
5.mount] failed with exit status 1: stderr:
Job failed. See "journalctl -xe" for details.)
dpkg: error processing archive /var/cache/apt/archives/firefox_1%3a1snap1-0ubuntu3~22.04.1_arm64.deb (--unpack
):
new firefox package pre-installation script subprocess returned error exit status 1
Errors were encountered while processing:
/var/cache/apt/archives/firefox_1%3a1snap1-0ubuntu3~22.04.1_arm64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

There were other apps/packages that defaulted to snap and produced similar failures. I think it might be related to some missing kernel defconfig switches that are needed for snap to run. Installing this might be a solution, but I haven't tried it yeat: https://open-store.io/app/snapz0r.fredldotme.

Edit: I was able to install firefox-esr.