> a failed BIOS update can brick the machine

As far as I am aware a failed bios/firmware update on any device can cause it to brick, thats why they always come with massive warnings everywhere. I personally do not just do bios updates because some OEM marketing said so. The old saying does me well, "If it aint broke dont fix it"

Some nicer boards have redundant copies of the BIOS so if you fuck up the update, it boots the old one.

Various enterprise boards with BMCs can flash the BIOS from the BMC even if the BIOS is fucked.

You might even be able to do that with Intel AMT, but I've never had occasion to try.