I found this quote from
here pretty interesting:
If an SDXC memory card is inserted into a PC or a host product that does not support SDXC memory cards, a message may prompt you to format the card. Do not format the SDXC memory card in a non-compatible host product; it will erase the data on the SDXC memory card and format the card for a different file system that will no longer work with SDXC host products.
This looks to me like SDHC devices can indeed address SDXC cards, and format them to a different file system. This is, can they only address the first 32Gb, or can they make use of all of that lovely 2Tb address space?
(we need to find whoever bought that Pandora for over 1000 quid on ebay and get him to test an SDXC card for us!
)