From what I've seen, WM5 would not do anything larger than 2GB and did not have drivers for SDHC. It was SD only.
WM6 adds SDHC compatibility. I think Palm said it could handle up to a 4GB card, but I recently saw in another forum where someone was successfully using an 8GB SDHC Sandisk card with no issues. They also claimed it could handle 32GB SDHC, but I don't know of anyone who's actually done it.
BTW, did you try reformatting the card from your PC with FAT32? |