setup-bootable under the bare alpine-standard-3.8.0-x86_64.iso throws an error about missing syslinux. The drive boots fine with uefi enabled in bios, however the mbr boot would complain about missing os.
I tried setup-bootable under alpine-extended-3.8.0-x86_64.iso and it ran with no errors. Hope it helps someone out there.
I also tried the dd method, however it felt hacky since in most cases a .cfg file editing is needed