I'm having the same problem. My 2215 read the SD card fine (although did have a rare problem once in a while). It lost all power, and after restoring everything from a backup, it does not now recognize the card (backup was from PC). It also doesn't turn on whenever card is inserted or removed, as it used to. I installed updated SD driver from here:
HP iPAQ Pocket PC h2200 Series SDIO Driver Update
but no joy. Anything else I can try? I hate to trash an otherwise good PDA.