Nintendo has managed to get it banned in some countries, like the UK and the Netherlands.
Both M3i Zero and R4i card can work on Nintendo DSi V1.4.3 console.
R4i 3DS is a new slot-1 flashcard for Nintendo 3DS console. It is made by r4ids.cn. the r4i 3ds card an run DSi games, play music, videos, and so on on Nintendo console. but it can't play 3DS games currently.
A r4i is a flashcart for the Nintendo DS/DSi. Which means, you are able to play movies or Homebrew DS games. To do so, you need a Micro SD Card. R4i card is the upgrade version of r4 card. It support Nintendo DSi and before version. you can enjoy games and medias (such as music, movie, e-book) with a r4i card.
The R4i will work in all DSis with the 1.0-1.3 firmware. It will NOT work it your DSi has been updated to the 1.4 firmware.
you need a R4i card
Yes
The R4i Gold 3DS card from r4ids.cn has all functions of r4i gold v2.0. It support Nintendo 3DS, DSi and DS, including the latest 3DS V2.1.0-4 console. If you want to get a good flashcard, I think the r4i gold is better than r4i gold v2.0.
r4i sdhc card is a most populare flashcard in the marekt. it works well on nintendo 3ds, dsi and ds console. the r4i sdhc firmware upate very fast. it offers good compatibiity. I think it is much better.
The best solution would be the R4i gold edition. To get it working you need to download the 1.41 kernel from r4ids.cn then update with a NDSL or NDS then it should work just like old ones on your dsi. Nintendo updated DSi V1.4.2 version on May 2011. most flashcard were halt. Now the r4i gold V1.4.2 from r4ids.cn and r4i sdhc v1.4.2 from r4i-sdhc.com can support Nintendo DSi V1.4.2 version.
If your r4i gold card is very old version, you may need to upgrade it for Nintendo 3DS V3.0.0 and DSi V1.4.3 console. But if the r4i gold is made after Aug 2012, it no need any upgrade. Just download the latest wood r4 v1.45 lernel for installation.
Nintendo DS/DSL/DSi are region free. Thus it does not matter where the hardware is from, it will play all games including all R4i cards. The latest r4i gold card from r4ids.cn is r4i gold 3ds card. It support Nintendo 3DS,DSi and DS console. with all versions, including EU DSi. R4i Gold from r4ids.cn support all DSi version. Such as: DSi V1.4.3, DSi V1.4.2, DSi V1.4.1 and DSi V1.4. It also support Nintendo 3DS, DS and DS lite. Good card.
No, there's an updated R4i that bypasses the 1.4 firmware. Check it out on the R4 website. Nintendo failed to beat the R4i once again.