The Situation

Phase 1: Triage From macOS (Blind)

Phase 2: The Tailscale Pivot

Phase 3: The Forensic Investigation

Finding #1: The Interface Name Heist

Finding #2: Docker Was Stealing the Interface Name

Finding #3: Energy Efficient Ethernet

Finding #4: The Root Cause 🔴

The Full Hit List

The Moment of Truth

The Architecture: How This Worked

What This Means A headless Raspberry Pi 4. A failed OS upgrade. No monitor, no keyboard, no network. One AI agent, one Jetson Nano, and a Tailscale connection. I run a headless Raspberry Pi 4 called homepi that handles critical home infrastructure: NextDNS, PiVPN/WireGuard, Tailscale, Docker, and Pi-hole. It sits in a closet with no monitor attached. Last week, I attempted to upgrade from Raspbian 10 (Buster) to 11 (Bullseye). The apt full-upgrade ran for hours, asked me a few config file questions, then went silent. The Pi never came back to the network. No DHCP lease. No SSH. No ping. The router showed nothing. I pulled the 32GB SanDisk microSD card and plugged it into my Mac. Finder showed only the FAT32 /boot partition. The ext4 root partition — where all the configs and logs live — was invisible to macOS. This is where most people would reach for a fresh SD card and start over. But I had an AI agent, and I wanted to see how far it could go. I shared a screenshot of the /boot directory with the agent. It immediately noticed something suspicious: cmdline.txt was dated December 31, 1979 — the Unix epoch. Could be corruption? Agent: "Step 1: On your Mac terminal, run cat /Volumes/boot/cmdline.txt" The file was intact — timestamp corruption only. The kernel command line looked fine. But the agent couldn't go deeper without reading the ext4 root partition. macOS can't do that natively. We tried installing macFUSE. Homebrew threw errors. The macOS version (26.5, a developer beta of what appears to be macOS 16) wasn't compatible with any available macFUSE build. Mac was a dead end. We needed Linux. I have a Jetson Nano on my Tailscale network. It runs JetPack (Ubuntu-based) and has a spare microSD slot. The agent suggested: Agent: "Plug the microSD into a USB card reader and connect it to the Jetson. Then we SSH in via Tailscale." I inserted the Pi's SD card into the Jetson's internal slot, and the agent connected over Tailscale SSH. Within seconds: Both partitions visible. Both mountable. We had full access to the patient. The agent mounted both partitions and began a systematic investigation. Here's what it found — in order: The Pi's dhcpcd.conf had a static IP configuration for eth0 at 192.168.1.100. But Bullseye introduces predictable network interface names — eth0 becomes something like enxxx:xx:xx:xx:xx:xx. The interface eth0 no longer existed. Fix: Added net.ifnames=0 biosdevname=0 to cmdline.txt to preserve traditional naming. But that wasn't enough. The agent dug into the kernel logs: The Broadcom Ethernet driver (bcmgenet) was loading and detecting the hardware correctly. But then Docker started first and its virtual Ethernet interface claimed the name eth0 before the physical NIC finished initializing. The real Ethernet had no name to grab. Fix: Disabled Docker and containerd from auto-starting — removed the symlinks from multi-user.target.wants. A known Raspberry Pi 4 quirk: Energy Efficient Ethernet can cause link negotiation failures with some switches. Fix: Added dtparam=eee=off to config.txt. Three fixes applied, but the agent wasn't satisfied. It kept digging through the systemd journal and found this in the syslog: This message repeated six times on every boot. dhcpcd was failing silently before it even started — and the Pi had no DHCP client running at all. The culprit was in /etc/systemd/system/dhcpcd.service.d/wait.conf: This was a DietPi-era override from Buster. In Bullseye, dhcpcd moved from /usr/lib/dhcpcd5/dhcpcd to /usr/sbin/dhcpcd. The override was pointing to a binary that no longer existed. Systemd tried to spawn it, got ENOENT, and gave up. Fix: One sed command: When the agent finished its audit, here's what had been fixed: Layers 1–3 were preventing the interface from working. Layer 4 meant even if the interface existed, dhcpcd couldn't assign an IP. The Pi was booting, the kernel was fine, the Ethernet hardware was detected — but the DHCP client was dead on arrival. I pulled the SD card from the Jetson, put it back in the Pi 4, and powered it on. The router showed a new DHCP lease. SSH connected. homepi was back. The recovery chain worked like this: The agent never had a keyboard plugged into the Pi. It never saw the boot screen. It never pinged the machine. Everything was done through forensic analysis of cold storage, mounted on a different machine across a Tailscale mesh network. We're entering an era where AI agents can perform legitimate sysadmin work — not just generating commands for humans to copy-paste, but actually diagnosing, investigating, and fixing systems autonomously. The agent didn't just suggest "try reinstalling." It: And it did this for a system that had literally no network access. The patient was in a coma, and the surgeon operated through a different body. This recovery was performed by Hermes Agent — an open-source AI agent framework that learns from experience and stores reusable skills. The entire session was conducted over Telegram, with the agent accessing the Jetson via Tailscale SSH and mounting the Pi's SD card for forensic analysis. All four fixes, the investigation logs, and the recovery workflow have been saved as reusable skills for future incidents. Templates let you quickly answer FAQs or store snippets for re-use. Hide child comments as well For further actions, you may consider blocking this person and/or reporting abuse