Can't update or install software

[kqlnut]

Did the error about the failed generation of a pacman keyring master key occur at another time? Because it isn't failing in the error log you posted, that's another thing failing (activating swap, not sure if this is expected, but it's not related to pacman). Also pacman shouldn't break with no internet connection at boot and neither should the flashing process have impact on this problem if you got so far as to successfully boot the OS.

Try again

Code:

sudo pacman -Syyu

If you are lucky, it was just a temporary outage and and by now it works again.

Otherwise, if the same error about not being able to resolve the repo mirror persists, try another mirror by putting it into /etc/pacman.conf directly under [core], [extra], [community], [alarm] and [aur] as described in this section. Other mirrors should be found in /etc/pacman.d/mirrorlist (not sure what's in there, I don't use Arch). Pick one and put it in each of the aforementioned sections (just change $repo to each of the sections). After you saved the file, run again

Code:

sudo pacman -Syyu

to force the package database to update.

Edit: I assume your internet connection on your device works. If you can't access the internet from it, then that's the problem of course.