I have a weird problem with a Secure Digital Card of mine. I use it on my iPAQ, running Pocket PC, and it's my primary method of transfering files from Linux to Pocket PC.
From my computer, I read the SD Card from a builtin USB Media Card Reader. My SD card is always at /dev/sda.
Recently I put a bunch of music files on it, then when I put it back in my iPAQ (after properly unmounting), my iPAQ couldn't read it. I put it back in my computer, and it mounted fine in Linux, and everything I put on it was still there. The only thing that I had changed, was I added a few files, and suddently it's unreadable on Pocket PC. I figured maybe somehow (although I couldn't see how) Linux had screwed up the partition. So I decided to reformat it (fat16, of course). I reformatted it in QTParted, wihout any apparent problems. I remounted it in Linux to see if it was working. No problem. I unmounted it, and put it in my PDA, still unreadable. I tried to reformat it again, directly with parted. Same results.
I decided that since I was trying to get it to work on a Windows CE machine, maybe Windows XP could format it properly. WinXP couldn't even recognize that a card was inserted, much less be able to format it. So I booted back into Linux, and I couldn't mount the SD card at all. It said the disk was spinning up, or something like that. Eventually, it stopped, and I could mount the card. It didn't seem to be giving me any problems. I could write to it without problems, but WinCE still couldn't read it. Right now, it's having trouble mounting again.
Does anyone have any idea how this might've happened, or at least how to fix it? I need to be able to format it with a single fat16 partition that's readable from a Windows machine. If I wait long enough, I should be able to mount (and therefore format) it again. So, what do I need to do to format it properly?