Okay, everything is working now that the card is correctly formatted. Boot speed seems a lot faster, and themes don't reset any longer. I was also able to update firm.boot in CTRNAND using GodMode. Mission successful; thanks much for the help!
Ah, I see! I thought I needed a script, but I found instructions to just copy it using GodMode.
And you're right: I'll need a third-party solution for FAT32. Annoying, but no big deal. I'll post an update when I've got it done.
Oh! When I went to format, the only options were NTFS and exFAT, so I didn't realize. A quick search just now tells me that I should be able to do it in FAT32 with the Disk Management tool or even third-party software if it comes to that, so I'll reformat and then copy the files back again...
I had a working Luma installation on my New 3DS XL that I installed a while back pretty much just for the Dai Gyakuten Saiban fan translation. A couple days ago, I was prompted to update the official firmware and did so; afterward, I got the "failed to apply 1 firm patch" message. Did my...