Question: are sdhc cards backwards compatible?
Answer: Because SDHC works differently than standard SD cards, this format is NOT backwards compatible with host devices that only take SD (128MB - 2GB) cards. Most readers and host devices built after 2008 should be SDHC compatible. ... SD Extended Capacity (SDXC™) card is an SD™ memory card based on the SDA 3.0 specification.