Josh Huang's Engineering Notes
Closing a Chip-Blocking Equivalence Problem to 0 NEQ
How I root-caused a hierarchical LEC failure everyone else had given up on, and shipped a FULL-EQ verdict with zero manual pin-constraints.
Engineering Notes
Case studies from 18+ years of chip design and infrastructure engineering — the debugging process, not just the result. Unlock individual articles for $5, or subscribe for $9/month unlimited — see Pricing.
Directing an AI Agent Through Production RTL, Not Just Autocomplete
What changes when you point an autonomous coding agent at real chip sign-off work instead of boilerplate — and what 20+ iterations on a production ISP module actually looked like.
The Kernel Bug Hiding Inside My Own Routing Table · 中文版
Selectively routing one console's streaming-app traffic through a Japan exit node, without touching its own login/matchmaking traffic — and the two independent kernel-level bugs that made it look impossible.
Why VLESS+REALITY, Not Just Another VPN Protocol · 中文版
The actual engineering reasoning behind picking a specific proxy protocol stack for personal infrastructure — and why the choice was about detection resistance, not encryption strength.
Running a Proxy Node on Fly.io · 中文版
Deploying a VLESS+REALITY node on Fly.io's global anycast platform — the free-tier tradeoffs, the IPv6-only gotcha, and why the deployment model matters more than the region you pick.
The Stream That Was "Running" But Completely Dead · 中文版
A 24/7 home camera → YouTube Live pipeline that looked healthy in every way that mattered, except it never actually produced a single frame — and the YouTube API lifecycle bugs waiting on the other side.
One Restreaming Hub, Many Cameras, One Silent Rejection · 中文版
Centralizing several cameras' RTSP feeds behind one restreaming layer solved the fan-out problem cleanly — until one camera with no audio track ran into a YouTube health check nobody expects to fail on video grounds.
The Packet Capture That Looked Perfect and Was Lying to Me · 中文版
A remote-desktop client's "cannot create tunnel" error came with genuinely compelling MTU/MSS evidence pointing at a network black hole — evidence that was real, reproducible, and completely unrelated to the cause.
Reading a Vendor's Own Binary to Prove Their Firmware Was Wrong · 中文版
A router firmware commit failed identically every time, with an opaque error and no source code to read —
until running strings on the vendor's own closed-source binary turned up the exact internal bug.
The One-Line Firewall Rule That Broke DNS for Everything · 中文版
A single, textbook NAT rule silently rewrote loopback DNS queries' source address, and every application on the machine lost name resolution at once — including the tool being used to push the fix.
The IPv6 Tunnel That Made the Whole Network Feel Slower · 中文版
Restoring IPv6 reachability behind a NAT'd home connection was the easy part. The mistake that made every device on the network feel sluggish was one boolean flag.
The API That Doesn't Wait: A Race Condition in Plain Sight · 中文版
An automation's two-factor login kept failing with "input is empty" even with the correct code — because the fix was in the order of two API calls, not their content.