Case study

fdsboot: Famicom Disk System boot ROM disassembly

fdsboot is a 6502 disassembly of the Famicom Disk System boot ROM, split into disk I/O, PPU, joypad, timer, sound, interrupt and random-number routines with include files for the console and FDS registers. The ca65/ld65 build reassembles fdsboot.bin and compares its CRC with the original and with a second revision, 3DS and Wii VC builds, and GW and TWIN variants selected by assembler flags. It serves as a reference when disassembling Famicom Disk System titles.

Targets: Firmware
Category: Independent reconstruction cases
Relationship: Independent reconstruction project
Sources reviewed: 2026-11-09

Copy as Markdown View JSON Cite

Requirements & limits

Prerequisites: Needs the cc65 assembler and linker (ca65, ld65) with make, or plan9port mk.
Prerequisites: The font and two data tables are extracted from the user's own boot ROM image with tools/extract.sh before building.
Limits: Where the source commentary and the assembly differ, the assembly is authoritative.
License: No licence file in the repository.

Cite

BibTeX

@misc{fdsboot-case,
  title = {{fdsboot: Famicom Disk System boot ROM disassembly}},
  howpublished = {\url{https://gitlab.com/segaloco/fdsboot}},
  url = {https://gitlab.com/segaloco/fdsboot},
  urldate = {2026-11-09},
  note = {Awesome REA entry: \url{https://awesomerea.org/resources/fdsboot-case/}}
}

Plain text

fdsboot: Famicom Disk System boot ROM disassembly. https://gitlab.com/segaloco/fdsboot (accessed 2026-11-09). Awesome REA entry: https://awesomerea.org/resources/fdsboot-case/

Useful? Star Awesome REA on GitHub2.4k

About this entry

The description was reviewed against primary sources.

Report an outdated entry Suggest a translation fix