Case study

p2afan: mapping ASPEED BMC fan control through the P2A bridge

p2afan investigates the Tyan FT77C-B7079 BMC and controls its ASPEED AST2400 fan PWM registers from the host through the PCIe-to-AHB bridge. Its write-up maps BAR1, the PWM block and firmware layout, while the Python controller computes duty from IPMI, hwmon or command output.

Targets: Firmware
Category: Independent reconstruction cases
Relationship: Independent reconstruction project
Sources reviewed: 2026-11-06
Evidence class: C2 code & docs, no demo or download

Stars: 1
Last commit: 2026-10-02
Language: Python
License (GitHub): MIT

GitHub data as of 2026-11-10

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Evidence

Observed: Code and documentation observed; no download method or demo found.
Checked: 2026-11-08

How evidence classes are assigned

Requirements & limits

Prerequisites: ASPEED AST2400/AST2500 BMC with an enabled, unlocked P2A bridge; root access, ipmitool and /dev/ipmi0.
Prerequisites: Source installation requires Python 3.11–3.14.
Limits: The measured register and sensor values come from one Tyan FT77C-B7079 chassis and must be re-derived for other machines.
License: MIT license.

Cite

BibTeX

@misc{p2afan-case,
  title = {{p2afan: mapping ASPEED BMC fan control through the P2A bridge}},
  howpublished = {\url{https://github.com/larkinwc/p2afan}},
  url = {https://github.com/larkinwc/p2afan},
  urldate = {2026-11-06},
  note = {Awesome REA entry: \url{https://awesomerea.org/resources/p2afan-case/}}
}

Plain text

p2afan: mapping ASPEED BMC fan control through the P2A bridge. https://github.com/larkinwc/p2afan (accessed 2026-11-06). Awesome REA entry: https://awesomerea.org/resources/p2afan-case/

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About this entry

The description was reviewed against primary sources.

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Primary sources

docs/bmc-re.md GitHub · larkinwc/p2afan · Revision 2fe3417
README.md GitHub · larkinwc/p2afan · Revision 2fe3417
re/firmware-findings.md GitHub · larkinwc/p2afan · Revision 2fe3417