Yes, it can record uncompressed, maybe this recorder will be a part of the solution? It will be available this summer (july for the "q" version, and august for the basic one).
The hyperdeck shuttle isn't supposed to record raw, only prores 4:2:2 10bits.. that's probably why you couldn't record raw i guess?
Or give a try again with the official firmware that canon will release tomorrow, the result can be different, i don't know..