yeah,not my intencion to update but as I said if you click the advice button that pops out with the update the software starts flashing itself.
for me at least not a big deal to lost all the settings,dind't have a backup but is not so complicated,can have the router re-configured in half an hour I think
but for ppl reading this that have a BRT-AC828 DON'T UPDATE YOUR FIRMWARE and DON'T CLICK IN THE ADVICE BUTTON until ASUS fix this mess
for me seems that asus doesn't want to provide me with support since they ask for my serial number that is in the office with the devide and not gonna return to the office without a good reason until the lockdown is finished,so I'll wait till I can return office and then try to use the recovery software for flashing-crashed routers and see if that lets me install an older update