How can a Malware infect UEFI/BIOS if updating it's hard for a normal user

By searching online i seen that a virus/malware can infect uefi or bios, but any guide to update it requires something like saving update file on a usb flash drive and boot the bios for manually start the update, so, if even for a user is hard to update the bios, how a virus can do that? how can bypass all this steps?

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