sync"

Raw disk access is a privilege in Linux, usually reserved for root.

You could have root change the permissions on the directory to allow another user or group write access.

You can’t make a usb bootable without root access iirc. If you already have a bootable usb like ventoy then you can load any goofy thing you want into it without root access and it’ll work.

Using dd or another third party flashing tool usually requires root to flash to usb.

Hope you find an answer, it would also be great to see the context of why you need to do it without root.

You could write it using your phone with https://f-droid.org/packages/eu.depau.etchdroid/

What's the concern?

I reckon it could be related to the permissions required to write to the usb. Perhaps udev rules could help here?

I did it on a humble user account using GNOME disks. Select the USB stick and choose restore image in the menu at the top right.

It is possible to format removable drives without root access through udisks2, e.g with gnome-disks or KDE ISO image writer. GNOME Impression is another tool that should work.

Just download the Balena watcher app image, flash whatever is you want, and then delete it. It's ridiculously easy.

Do you not have root access or are you worried about using root access? Sudo will do the trick, you don't need to login as root directly.