Loool I just realized you had written an entire paragraph precisely about that just 3 posts above my question, sorry for not having searched a bit more thoroughly and thanks for kindly repeating yourself !Yes you can, its listed on Hekate's GitHub page.
Anyway all of my efforts to keep my slot unupdated until then have been reduced to ashes by just one *!#?X! misclick on the ReiNX payload, which has the very good idea of booting ReiNX even if you don't have any files related to it on your SD, and well since you need the nogc file on your SD for ReiNX to disable the card reader it booted without disabling it and must have updated it... If an untethered exploit that requires a cartridge and a firmware under 4.0 is discovered I'm gonna be saaaaaalty !