Stuck on Day 1 of homelab build — M720q BIOS not detecting USB boot media
Hey r/homelab — first-time poster, putting together my first homelab and I'm completely stuck before I've even installed an OS. Could someone with M720q experience point out what I'm missing?
The build
- Lenovo ThinkCentre M720q Tiny (Amazon Renewed, ~$250)
- Model: 10T8S53S00 | Serial: MJ082ZQS
- CPU: i5-8400T (6 cores)
- RAM: 16 GB DDR4
- Storage: WDC PC SN520 SDAPMUW-512G-1001 (500GB NVMe)
- BIOS: M1UKT45A (07/11/2019) ← I know this is old, more on that below
- Goal: Proxmox VE 9.1 host for a GRC-focused homelab (pivoting into IT audit/compliance, not DevOps)
The boot media
- SanDisk Ultra Flair 128GB USB 3.0
- Ventoy 1.1.12 installed (originally MBR, re-flashed as GPT + Secure Boot enabled)
- Proxmox VE 9.1 ISO copied successfully (1.4 GB, verified on the drive)
What I tried — exhaustive list
BIOS configuration:
- Reset to defaults, then applied a hardened baseline (Admin password set, Computrace disabled, TPM enabled, etc.)
- USB Support: Enabled
- USB Legacy Support: Enabled
- USB Enumeration Delay: tried both Enabled and Disabled
- All USB ports (front + rear): Enabled
- Smart USB Protection: tried Read-Only, then Disabled
- Secure Boot: Disabled
- CSM: tried both Disabled (UEFI Only) AND Enabled (Auto + UEFI First boot priority)
- Boot Device List F12 Option: Enabled
USB testing:
- Tried every rear USB port (SS3, SS4, SS5, SS6 — all USB 3.0 "blue")
- Tried front USB ports
- Full power drain: shut down, unplugged power cable, held power button 30 seconds, replugged
- Plugged USB in BEFORE powering on every attempt
- Re-flashed Ventoy in GPT mode with Secure Boot Support enabled
- Verified the ISO is on the Ventoy partition (1.4 GB, not corrupt)
- USB works perfectly on my Windows laptop — Ventoy + ISO both visible
What I see in F12 boot picker
Every single attempt:
Startup Device Menu
M.2 Drive 1: WDC PC SN520 SDAPMUW-512G-1001
Legacy: WDC PC SN520 SDAPMUW-512G-1001
Enter Setup
That's it. No USB entry of any kind. Not even an empty USB HDD: slot — the BIOS doesn't see the SanDisk at the enumeration level, period.
My current hypothesis
BIOS M1UKT45A from July 2019 has a known issue with USB device enumeration. Lenovo released several BIOS updates for the M720q since then. I'm pretty sure I need to flash to current firmware before I can boot from USB.
What I'm asking
- Has anyone with an M720q hit this exact issue? Did a BIOS update fix it?
- Any chance I'm missing a hidden BIOS setting? This BIOS doesn't have "Always On USB" or "USB Power Sharing" toggles that I can find.
- Is there a way to flash the BIOS update from inside Windows (the M720q has the previous owner's Windows install I haven't wiped yet)?
- Any chance it's the SanDisk specifically? Should I try a different brand stick?
- Worst case — can I install Proxmox from inside Windows somehow? Or am I stuck until I get USB boot working?
Context on me
This is my first homelab. I'm pivoting into GRC / IT audit. The whole point of this build is to have hands-on experience documenting hardening baselines and control implementations. I'm following Professor Messer Sec+ alongside this. I want to do it right, even if Day 1 is humbling.
Appreciate any help. Happy to provide more screenshots/info.
— Cue
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