Visit the official website listed on your card (e.g., r4isdhc.com or trusted archives like r43ds.org ).
The R4 SDHC 2015 Dual Core lacks the necessary cryptographic keys to boot on a DSi or 3DS without a custom firmware (CFW) on the console itself. Even with CFW, performance is spotty. For DSi/3DS, consider newer carts like the or Stargate 3DS . r4 sdhc 2015 dual core firmware
The dual core firmware on the R4 SDHC 2015 provides a number of benefits, including: Visit the official website listed on your card (e
Don't throw that card away just yet!