Ripping Sonic Boom:Fire and Ice without a N3DS

Hi!!!

I'm trying to rip the models (I really want one of them) from Sonic Boom: Fire and Ice.

Because i don't have a N3DS I'm trying to use this tutorial:

I'm using the info from here: https://www.vg-resource.com/thread-28039-page-2.html

I tried with a .3ds and with a .cia

- For the cia the makerom failed converting to *.cci.

- For the 3ds i followed all the instructions from the 3ds.Rom.Tools, but it gaves an error in some point...

What kind  of rom i need exactly to rip the models without a nintendo 3DS?

Thanks a lot!

P If someone want to collaborate with me and do the step that give me error he will be credited in my project!