Auto-Restart on Power Loss — Consumer Mini PCs (2026-07-04)

Context

n5pro (10.0.20.91) is a Micro Computer N5 PRO (AMD Ryzen, AMI BIOS 1.01, no IPMI/BMC). Needs to auto-restart after power outage for Ceph OSD availability.

Problem

Enterprise servers have IPMI/BMC with "Restore on Power Loss" configurable via ipmitool. Consumer mini PCs lack IPMI — the setting lives in BIOS NVRAM only.

AMI BIOS Limitations

The "Restore on AC Power Loss" / "State After G3" setting is stored in AMI proprietary NVRAM variables (AMD_PBS_SETUP, AmdSetup) — not standard EFI vars.
These variables are opaque binary blobs; writing them blindly risks bricking the board.
efivar / efibootmgr cannot parse or modify AMI setup menus.
Conclusion: This setting must be changed manually in BIOS UI.

BIOS Instructions (manual, one-time)

Boot → press Del or F2 → enter BIOS Setup
Navigate to Chipset → South Cluster Configuration (or Advanced → Power Management)
Find State After G3 (or Restore on AC Power Loss)
Set to Power On (or S0 / Last State)
Save & exit (F10)

Wake-on-LAN as Fallback

WoL can wake a powered-off machine IF:

The NIC receives standby power (machine is plugged in, PSU switch on)
WoL is enabled in BOTH BIOS and OS

⚠️ WoL does NOT help after a complete power outage — the NIC has no power. It only helps for soft power-off (S5 state with standby power).

Enabling WoL Persistently

Identify the Physical NIC

Mini PCs often have bond/team interfaces. Check which physical NIC supports WoL:

# List all interfaces
ip link show

# Check WoL support on each physical NIC
ethtool nic0 | grep -i "wake"
# Supports Wake-on: pumbg  ← good
# Wake-on: d         ← disabled

# Enable WoL magic packet
ethtool -s nic0 wol g

⚠️ Bond interfaces (bond0) don't have WoL — enable it on the physical slave (nic0).

Persistent systemd Service

# /etc/systemd/system/wol-enable.service
[Unit]
Description=Enable Wake-on-LAN
After=network.target

[Service]
Type=oneshot
ExecStart=/sbin/ethtool -s nic0 wol g
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

systemctl daemon-reload
systemctl enable --now wol-enable.service

Triggering WoL Remotely

# From any machine on the same broadcast domain
wakeonlan <MAC_ADDRESS>
# or
etherwake -i <interface> <MAC_ADDRESS>

Node Inventory: n5pro (10.0.20.91)

Property	Value
Hardware	Micro Computer (HK) Tech N5 PRO
BIOS	AMI 1.01 (2025-10-24)
CPU	AMD Ryzen
NVMe	128 GB AirDisk SSD (MAP1202 DRAM-less)
SATA Controller	JMicron JMB58x AHCI, 5/5 ports implemented
USB Boot	SanDisk 3.2Gen1 14.3 GB (Proxmox installer)
Network	bond0 (nic0 + eno1), MAC: 38:05:25:37:8e:08
WoL	Enabled on nic0, systemd service active
BIOS Auto-Start	⚠️ MANUAL — needs "State After G3 = Power On" in BIOS
Ceph OSDs	None yet — prepared for 2x 3TB HDDs

General Decision Matrix: Auto-Restart Methods

Hardware Type	Method	Remote Config?
Enterprise server with IPMI	`ipmitool chassis setenv`	Yes
Consumer PC with AMI BIOS	BIOS "State After G3"	Manual BIOS
Consumer PC, no BIOS option	WoL + external waker	Partial (needs power)
PiKVM / BMC add-on	Virtual media + IPMI emulation	Yes

Pitfalls

Don't write AMI NVRAM vars blind — AMD_PBS_SETUP is an opaque binary blob, not a simple key-value store. Writing wrong bytes bricks the board.
Bond interfaces don't support ethtool WoL — target the physical slave interface, not bond0.
WoL after full power outage is useless — NIC has no standby power. Only BIOS "Restore on AC" helps.
AHCI port count misleading — some controllers advertise N ports but implement fewer. Check dmesg | grep "ports implemented" (e.g. OptiPlex 3070: 5 ports shown, only 1 implemented = port mask 0x1).

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