Resetting used hardware to factory default

I’ve just purchased a used Omnia. I want to make sure that the previous owner hasn’t tampered with the firmware or bootloader. Should factory reset be sufficient, or is there a way I can flash a new factory firmware image to make sure?

Maybe I’m being paranoid?!?

this may help

Perhaps notworthy for Rollback to factory reset is the presumtion that it

rolls back to the first snapshot (the first snapshot has been created in the factory).

If that snapshot however been wiped by the previous owner the router may not rollback to factory settings.
To be save perhaps re-flashing the router is the better choice.

Thanks, I’ll probably re-flash from USB drive.