The Supper Dstwo card can perfectly support the 3ds v6.2.0-12 now.
The supper DSTWO Card website has released the good news on their official website:
firmware v1.21 support DSi 1.45 and 3DS 6.2.0-12x Download from here.
Important: Please make sure the power is enough! And don't do anything unnecessary!
If you own a supper dstwo card you can kindly download the firmware to v6.2.0-12.