BIOS stage 2 subtract overflows

I'm attempting to migrate my kernel from v0.10.x of bootloader, and after switching to v0.11.x and running in QEMU, I see a panic in the BIOS bootloader's stage 2 code:

The subtract that overflows appears to be on this line: https://github.com/rust-osdev/bootloader/blob/fa87d01a4a166b51412d162c8343bc2565bdbee0/bios/stage-2/src/fat.rs#L96-L99

I'm creating the image using BiosBoot::create_disk_image, and passing it to QEMU with the arguments -drive format=raw,file=/path/to/bios.img as suggested in the documentation on creating a disk image, so I don't think anything about my configuration is particularly out of the ordinary. I can provide additional information if there's anything that would help, though.

Bootloader version: 0.11.2
QEMU version:

$ qemu-system-x86_64 --version
QEMU emulator version 7.2.0
Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers

Start in bios/stage-2/src/fat.rs at lines 96-99 and reproduce the panic with BiosBoot::create_disk_image and QEMU using the documented raw-drive arguments. Compare the behavior between bootloader 0.10.x and 0.11.2, then verify that the generated BIOS image boots in QEMU without the stage 2 subtraction overflow.