I just got my hands on my New 3DS (Japanese region version):
http://postimg.org/image/bdiig1vtj/
It came with Firmware 8.1.0 out of the box, and my DSTwo with latest firmware seemed to boot up fine on it.
If any of you have any questions, feel free to ask here and I'll try to answer to the best of my ability.
Please also note that my responses are based on my experience with the unit; it may differ for you or other individuals.
If you also, like me, just got your New 3DS/LL, please feel free to add your input to this thread.
Update 1: I just upgraded it to latest firmware (9.1.0-20J) and my DSTwo with latest firmware still boots up fine. Woohoo!!!
Update 2 (Nov. 1): It's a bit superfluous info, but after updating to firmware 9.2.0J, my DSTwo with latest firmware still worked.
http://postimg.org/image/bdiig1vtj/
It came with Firmware 8.1.0 out of the box, and my DSTwo with latest firmware seemed to boot up fine on it.
If any of you have any questions, feel free to ask here and I'll try to answer to the best of my ability.
Please also note that my responses are based on my experience with the unit; it may differ for you or other individuals.
If you also, like me, just got your New 3DS/LL, please feel free to add your input to this thread.
Update 1: I just upgraded it to latest firmware (9.1.0-20J) and my DSTwo with latest firmware still boots up fine. Woohoo!!!
Update 2 (Nov. 1): It's a bit superfluous info, but after updating to firmware 9.2.0J, my DSTwo with latest firmware still worked.