Some people recently mentioned that homebrew DSi Wifi "does't work" yet. Actually, it's more like this:
Old DS wifi, with max 2Mbit/s, and with older encryption standards
* Old DS wifi on older DSi models is already working perfectly (eg. with "dslink" for wifi uploads from PC to DSi).
* Old DS wifi on newer DSi models (and 3DS consoles in DSi mode) should work the same, but I don't know if anybody has ever tested it yet (?) as far as I know it's still in "untested" stage rather than being "(not) working" (and if it doesn't work then it does probably require only some tiny initialization to switch the wifi hardware to DS mode).
New DSi wifi, with higher transfer rates and newer encryption standards
That's done using a "firmware" running on the wifi board, and a "driver" on the main cpu (as there's no OS on the DSi, this "driver" would have to be part of the DSi game/executable, and it would then communicate with the "firmware" via the DSi's SDIO bus).
The "firmware" is installed/initialized by the Launcher when booting the DSi, so one won't have to worry about that step. And Atheros does have released the "firmware" as open source, which has already helped on rev-engineering some of the inner workings of the DSi wifi hardware.
Almost certainly Atheros did also release the "driver" as open source. The main issue would be finding the correct source code version that works with the DSi hardware, and then, it would be very helpful if "compiler people" could test if it's actually working on DSi (I am more in ASM stuff and don't want to compile HLL code, but if somebody finds some potentially working source code versions then I could help on checking which version is looking best for DSi (*), and on tracking down issues if it doesn't work out of the box).
(*) there is also info in gbatek about wifi "firmware" functions, and, with that info, it should be possible to find out which source code version is having matching "driver" functions.
PS
There are three hardware versions (two for older/newer DSi's, and at least one for 3DS (which is also part of the "DSi" family since it can play DSi software)):
* DSi - DWM-W015 Wifi Daughterboard - Atheros AR6002G-AC1B chip
* DSi - DWM-W024 Wifi Daughterboard - Atheros AR6013 chip
* 3DS - DWM-W028 Wifi Daughterboard - Atheros AR6014 chip
Concerning the "driver" side, they should be all backwards compatible with the old DWM-W015 version.
PPS
I am still needing one DWM-W015 and one DWM-W024 wifi daughterboard (just in case somebody has spare wifi boards, or bricked DSi consoles). I would gladly get that stuff as 'hardware dontations' for taking that boards apart.
Old DS wifi, with max 2Mbit/s, and with older encryption standards
* Old DS wifi on older DSi models is already working perfectly (eg. with "dslink" for wifi uploads from PC to DSi).
* Old DS wifi on newer DSi models (and 3DS consoles in DSi mode) should work the same, but I don't know if anybody has ever tested it yet (?) as far as I know it's still in "untested" stage rather than being "(not) working" (and if it doesn't work then it does probably require only some tiny initialization to switch the wifi hardware to DS mode).
New DSi wifi, with higher transfer rates and newer encryption standards
That's done using a "firmware" running on the wifi board, and a "driver" on the main cpu (as there's no OS on the DSi, this "driver" would have to be part of the DSi game/executable, and it would then communicate with the "firmware" via the DSi's SDIO bus).
The "firmware" is installed/initialized by the Launcher when booting the DSi, so one won't have to worry about that step. And Atheros does have released the "firmware" as open source, which has already helped on rev-engineering some of the inner workings of the DSi wifi hardware.
Almost certainly Atheros did also release the "driver" as open source. The main issue would be finding the correct source code version that works with the DSi hardware, and then, it would be very helpful if "compiler people" could test if it's actually working on DSi (I am more in ASM stuff and don't want to compile HLL code, but if somebody finds some potentially working source code versions then I could help on checking which version is looking best for DSi (*), and on tracking down issues if it doesn't work out of the box).
(*) there is also info in gbatek about wifi "firmware" functions, and, with that info, it should be possible to find out which source code version is having matching "driver" functions.
PS
There are three hardware versions (two for older/newer DSi's, and at least one for 3DS (which is also part of the "DSi" family since it can play DSi software)):
* DSi - DWM-W015 Wifi Daughterboard - Atheros AR6002G-AC1B chip
* DSi - DWM-W024 Wifi Daughterboard - Atheros AR6013 chip
* 3DS - DWM-W028 Wifi Daughterboard - Atheros AR6014 chip
Concerning the "driver" side, they should be all backwards compatible with the old DWM-W015 version.
PPS
I am still needing one DWM-W015 and one DWM-W024 wifi daughterboard (just in case somebody has spare wifi boards, or bricked DSi consoles). I would gladly get that stuff as 'hardware dontations' for taking that boards apart.