Smash Stack exploit requires a non-SDHC card. These are usually lower end, lower size, older cards. The only one I have that is non SDHC is a 2GB one from a bunch of years ago. Most new ones are SDHC and will not work for the exploit. My guess is that whoever said that meant to actually say that SDHC didn't work, not that SD itself didn't work. I can confirm the Smash Stack exploit still works 100% on the latest system update with a supported SD card.