Changes

I myself can confirm that a 256 GB microSD card works fine within my personal New 3DS XL. The system does take ~25 seconds starting up though (part of this might be me running an emuNAND off it as well). It also takes forever loading large numbers of application tiles. My O3DS also runs a 128 GB microSD, also with an emuNAND, taking about ~20 seconds on boot.

I myself can confirm that a 256 GB microSD card works fine within my personal New 3DS XL. The system does take ~25 seconds starting up though (part of this might be me running an emuNAND off it as well). It also takes forever loading large numbers of application tiles. My O3DS also runs a 128 GB microSD, also with an emuNAND, taking about ~20 seconds on boot.

<br>I'm pretty sure the SD card controller can handle even larger SD cards, but I simply don't have larger SD cards to test. I also think each card and each system will react differently to each other, I had the O3DS microSD in my N3DSXL for a long time (also using an emuNAND, it's a lot easier to replace an SD card than a motherboard) and if I remember correctly it also took forever booting up, longer than the O3DS takes right now.

<br>I'm pretty sure the SD card controller can handle even larger SD cards, but I simply don't have larger SD cards to test. I also think each card and each system will react differently to each other, I had the O3DS microSD in my N3DSXL for a long time (also using an emuNAND, it's a lot easier to replace an SD card than a motherboard) and if I remember correctly it also took forever booting up, longer than the O3DS takes right now.