Well, I don't know what I did...mostly ejecting and reinserting the SD card. Before, it was showing contents on the card, then it started showing nothing. I can't recall if I did anything else before that to have any effect on it, except that I did flash the ROM and reverted to a clean install of the Sharp 1.40 JP. I don't if this had anything to do with it (it was something I was planning on doing, not actually in response to the SD card not working).
After I saw that nothing seemed to be on the SD card, I tried fdisk and it worked, then I formatted to ext2 again. So...I don't really know what happened and I probably never will
obscurite:
This is a previous thread that maybe you hadn't seen and might help you.
https://www.oesf.org/forums/inde...matting+sd+card