They do. Even back in their pre-UEFI days, it was possible to flash BIOS from a properly-formatted USB drive by holding down a magic key combination at power on. But it was not exactly publicized as a supported method.
Never forget Voyager, where Torres could invent a brand new method of transporter lock and implement it on-the-fly all through a console on the bridge, but even the bio-neural gel packs weren’t smart enough to get a power requisition down to the bottom decks without someone putting it into a padd and physically walking it down there.
They really didn’t give much direction at all on how Klingons should look back then. The actor and makeup artist basically came up with it on the spot.