I didn't have to update any script, the community-build I flashed doesn't even require the blob-partition yet (that requirement will only come in the next build). I just confirmed that the blob-partition is now properly writable from fastboot mode. I don't think the sailfish-x build will ship with the flash.sh but simply using this one which is in the same folder as the flash.bat in the repo should most likely work with no/only minor modification