Did you try formatting the card in the Zoom?
Yes, I formatted the card in the Zoom. It said I had six hours and some number of minutes remaining in four-channel mode.
Also, I wonder if it would work if you formatted the card on a PC as FAT32, and then created the folder structure that the H2 format creates. The 2GB files size is a limitation of FAT16 and the cluster size used to format the disk. That's why I say this could very well be a hardware issue with the maximum file size, even if a flash allows for larger cards.
I am unable to do anything with the card at the moment, even format it.
Also, the maximum file size under FAT16 is 2GB because that's also the largest partition size possible with FAT16. The card, after formatting and before breaking, appeared to be formatted FAT32 by the Zoom, as it was a single 8GB (well, about 7.5 really) partition.

It's actually the first real jamming I've done this year. Hopefully I'll have some better thought out lines and some completed song structures next time....