welp, flipper says is needs an sd card with fresh databases. tried to update gave me a buncha errors.
SD one, or just retry it and wait a couple of minutes after starting the flash, even if the reboot does not happens by itself, just do a quickreset with the back+left and if the fw copy itself finished, often it will just continue the update like it should. Not sure why but recent updates seem to get stuck on the reboot somewhere, and if you give it a reboot manually it seems to pickup again and actually finish the flash successfully anyways.