There is a separate fix for their previous discontinued model the R4i SDHC v1.4.1 as well.
(If the box on your R4i card shows v1.4.1, this is yours) Pick up the Nintendo console you are going to use to flash your R4i 3DS.
The update will take between 5 and 8 minutes to complete.
Once it’s done, you should find that the R4i 3DS / R4i SDHC firmware version will now be 1.4.3 if you check in settings, and therefore it will now be compatible with the Nintendo DSi / DSi XL latest firmware.
For a video of this upgrade process, watch DSCard World’s extremely helpful R4i 3DS Upgrade video (click link to see) to see the process in action!