System Transfer is functionality that was added with the 2.0.0-2 June 6/7 2011 system update, which allows you to transfer DSiWare, recorded audio from the Nintendo DSi Sound title, "internal memory" pictures, WFC configuration, from DSi to 3DS. On DSi this is done with the "Nintendo 3DS Transfer Tool" that is downloaded from DSi Shop, while on 3DS System Transfer is accessible in the System Settings. System Transfer can also be used to transfer 3DSWare to other 3DS systems.
DSi System Transfer
With the DSiWare DSi->3DS transfer, savegames are not transferred. When transferring DSiWare, the DSi system transfer title will send a SOAP request to the DSi Shop server, this transfers the DSiWare license/ticket to the 3DS shop account. The DSi title will then delete the ticket from NAND. The 3DS will then download the ticket, tmd, and content immediately from shop/CDN.
The 3DS broadcasts beacons with Nintendo tag vendor 0009bf. This includes the 3DS user-name, and possibly some consoleID? The DSi authenticates/associates with some binary SSID. The rest uses cleartext ntr/twl multi-cast communications, a lot of keep-alive frames are sent.
The DSi will then send its country code, username, and serial number to the 3DS, 3DS will send its country-code/username/serial# to DSi as well. The DSi sends a list of owned titles to the 3DS. The 3DS then seems to query the shop server via SOAP to check which titles may be transferred, it then replies to the DSi with a list of titles(of the titles which were sent to it) that can be transferred. When the user selects which title to transfer, DSi sends the banner of that title to the 3DS and many frames later the titleID.
When the DSi transfer tool and 3DS transfer tool startup, the DSi sends HTTPS SOAP requests to ecs.t.nintendowifi.net, ias.t.nintendowifi.net, and cas.t.nintendowifi.net. The 3DS sends HTTPS (mostly SOAP, unknown why the first one is used) requests to nus.c.nintendowifi.net, ecs.c.nintendowifi.net, and cas.c.nintendowifi.net. When entering the transfer DSiWare list menu, DSi requests from ecs* and cas*, 3DS does likewise. The 3DS system transfer will not allow you(likely server-side or so) to transfer etc at all unless you have the latest system update.
When DSi sends the title list, after the first 6 bytes of the 802.11 data payload, is the below header. Following the header is the list of titles.
|0xd||0x48||All 0xFF bytes.|
3DS title list header:
|0x18||0xf||3DS serial number|
|0x27||0x11||Bytes alternates between 0xbd and 0xf7: first byte is 0xbd, second is 0xf7, third is 0xbd etc.|
|0x28||0x8||Unknown, ASCII 3DS ticket consoleID used with DSi Shop SOAPs for the DeviceId?(Unconfirmed)|
Title record from DSi and 3DS
Total record size is 0x128 bytes.
|0x20||?||Sometimes the title name is stored here?|
3DSWare transfer is now available 3.0.0-5. See also3DS System transfer
Nintendo of Japan System Transfer page.