[TW] SB shim seems to be broken

Hey, tried to install TW today on a secondary machine, but the Install ISO and installed system don't boot because my Firmware tells me the shim can't be verified: security violation. and shuts off. Running this on the latest Dell Latitude 5490 UEFI firmware (as of today - 1.28.0) with only the MS and MS third-party key in the database.