I updated my r4i card to the latest version (v1.74b), after that i used a ds lite to update it so that i can use it for my 3ds (v6.3.0-12U) but when i go to the update page there is no option for me to upgrade, it only says support model: NDSL, NDSI 1.45, 3DS 5.0
I suggest you go back to your cart's website and re-read it several times. What you need to know and is now asking are already clearly written in red on the top of the page since September 16th.
We suggest you to follow this instructions to update your r4i sdhc 3ds rts card to work on 3ds v6.2.0-12. http://what-is.3ds-r4i.com/what-is-the-instruction-of-how-to-update-r4i-sdhc-3ds-rts-card-to-support-the-latest-3ds-console-117/ Please be noted that it's unnecessary for those R4i-SDHC RTS cards which support N3DS V6.2.0-12 to work by updating the firmware.