Updating r4ds ii
Later on, the original R4 team would go on to make cards that were also compatible with newer DSi and 3DS consoles.
These were called the R4i SDHC, and the R4i 3DS respectively.
Back then, games and applications were broadly under 100MB in size and this was often fine.
However, as applications became more complex so too did people's desires for more memory without having to swap out Micro-SD cards all the time.
The spring mechanism would stop working, trapping Micro-SD cards in the R4 card or making them very different to take in or out.
As a result, they changed the design to a push slot instead.