An update has been released for the Hitachi G1000 that gives it SDIO and SDIONow compliance. Unfortunately it is only available from the hard-to-access Sprint Downloads page (not even on Hitachi’s G1000 page currently).
http://www.sprintpcsinfo.com/phones/hitachi/G1000SDIO.CAB
To install, transfer the file over to the G1000 and open it from there. This is not a ROM update, so you will have to reinstall it if you ever hard reset the device.