Reverse engineering is the map, but implementation is the grind. It’s one thing to piece together findings that make sense from reverse engineering; it’s another to successfully bring up a PHY or realize you need to swap the PHY firmware just to switch from an optical SFP to a DAC cable. These are the silent hurdles that determine whether a port actually links up.

A Massive Systems Engineering Task

Developing a custom Network Operating System (NOS) is a significant software project defined by its physical constraints. The moment you hit the metal, you have to reconcile your code with the specific, often undocumented realities of the silicon. Working with an Edgecore AS5610-52X has been a stark reminder that hardware requirements are absolute; if you don’t meet the specific firmware or timing needs, the system simply won’t work.

The Versioning Maze

Navigating this gear highlights a persistent frustration in enterprise hardware: the rigid coupling of specific firmware to specific hardware revisions.

In this build, I’ve been hitting breaking changes at every turn. Between hardware-specific NOS builds and versioning gaps in open-source components, it felt like we were fighting the existing stack rather than building our own. While we still use those vendor builds as vital references to understand the hardware’s behavior, I’ve shifted strategy. I’m now using my own reverse-engineering data to bypass these requirements and construct the stack from the ground up.

The Deep Dive: 802.3 and the Physical Layer

Managing the underlying plumbing is where the real complexity lives:

• SerDes, PHY, & Retimers: Tuning high-speed serialization and signal integrity for stable links.

• I2C & EEPROMs: Talking directly to SFP+ cages to read transceiver data.

• The ASIC Interface: Bridging internal switching logic with physical hardware.

The Partitioning Puzzle

Even getting a standard Debian base to play nice with the ONIE loader was a struggle. These systems require a “bulletproof” boot architecture:

• A/B System Partitioning: Logic to toggle dual OS images for fail-safe upgrades.

• Overlay File Systems: Keeping the core system immutable while allowing persistent configurations.

The Grind

Reverse engineering is a trial-and-error process involving heavy static analysis with strings, objdump, and hex editors. It’s a lot of work (Even with help from AI), and there’s always room for mistakes—but moving from “theoretically possible” to a stable boot is where the real learning happens.

The foundation is finally holding. It’s still a work in progress, but the path forward is much clearer now that I’ve moved away from fighting inherited versioning conflicts and toward building a stack that actually respects the hardware’s constraints.