A common myth that presumably Nintendo circulated prior to the release of their new 3ds console was that a R4 card could “brick” or damage your console permanently. This myth was circulated in order to deter potential users of new 3DS consoles with R4 cards. The truth of the matter is that no r4 card, even a R4 3DS card, can damage your console whether it be an early DS, DS lite, DSi, DSi XL or even a 3DS console. Nintendo and game manufacturers want you to buy original game ware rather than some users using r4 cards for pirated software, which they do not have the license to use. There is millions of pounds a year lost in revenue due to the existence of such devices such as the R4 card.
What can occur though is that if a upgrade process is run on older R4i 3ds cards (used on 3ds consoles 220.127.116.11 or DSI 1.43 firmware) and half was through running the upgrade process on the r4 card, your console runs out of power, your r4 card will be damaged permanently. This is because the R4 card manufacturers strictly advise prior to trying to upgrade your R4 card, to ensure that the upgrade process is not interrupted. To ensure the process goes uninterrupted you may want to do the following to avoid damaging your R4 card:
There is no fix to a bricked R4 card as a result of not following the guidelines so we recommend you follow the above simple points to protect your investment that you have made in your R4 3ds card or the R4i card.