Hacking MH4U retail cart save dump to N3DS

[neo_hito]

So I've been playing the MH4U on a good ol' 3DS 4.5 fw in GW 9.5 emunand, sadly this is a retail card so its via classic mode.
Been trying a couple of things but no dice:

• GW classic can't run .cias ... great
• GW mode doesn't read retail cards - savedatafiler can't even see it?
• 4.5 CFW I think it sees the cart but it says broken... is it because the cart supposed to have 6.x encryption?

So basically am I doomed to keep playing on the old 3DS unless there's a 9.5 CFW or something?
there's no way to dump the save and convert to the new encryption and then inject back to the cart?