wudump writing 0 byte game.wud files on USB NTFS harddrive, despite over 200 GBs of free space

[wertercatt]

I managed to get one disc to dump properly, but I have been unable to replicate the success since. wudump writes common.key and game.key properly, and there are no errors visible during the actual dumping process. However, after wudump finishes and exits out to the system menu, removing the drive and plugging it into a computer reveals that game.wud is an empty file. Dumping multiple games will result in all the subfolders and game/common.key files being created properly for each game, but the game.wud always being 0 bytes. The only cause I can think of is that when the System Menu gets execution, it interrupts with the prompt to reformat the drive to the Wii U's special USB filesystem, which may be preventing wudump from successfully writing to game.wud?