For some reason I can't install to 64, 128, or 256GB SD Cards, but when I tried to use a 32GB card it worked fine.
With the larger cards, the install goes fine, but on boot I get the error:
At a guess, it's BIOS related? And there may to 2 BIOS' involved, the host adapter and the motherboard.
ryecoaaron has way more experience with something like this. I've never seen anything like it.
(The only thing that comes to mind is, with building a USB thumb-drive and the Debian installer said something like, "error partitioning drive - reboot recommended" or something like that. I rebooted, went through the install routine again and on the second time around all was fine.)
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If I were you, with 24GB, I'd disable swap file as @gderf suggested. (BTW - the instructions for that is in the GUI, on the Flash Memory plugin page when installing activating it). Then, as a work around, have you thought about partitioning the SD-card? That might work and Gparted will do it. Size the first partition for 30GB and leave the rest unallocated. Wear leveling should be able to use it.
With that much RAM, you should be fine without a swap file. I'm running a little Atom box with 4GB ram, no swap file, and a 4TB ZFS mirror with zero problems.