Pure stdlib, no mkfs.exfat: writes a Main Boot Sector + its boot-region
checksum + a backup region, the 32-bit FAT, an allocation bitmap, an
up-case table (with its checksum), and a root directory carrying the
bitmap/up-case/label entries plus a seeded HELLO.TXT file set. --serial
sets the volume serial (the content id-path); --verify re-reads the VBR,
recomputes the boot checksum, and validates each file set's checksum.
Cross-checked against the engine: the Zig exFAT engine mounts a
Python-produced image and reads HELLO.TXT through a case-insensitive
resolve ("exfat hello danos"), proving the tool and engine agree on the
layout — VBR, geometry, bitmap, up-case, and the entry-set checksum. No
image is committed; the drill (step 8) generates one per run.
Daniel Samson
2a6d604577