Ubuntu 20.04 Wi-Fi Adapter Not Detected

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Wireless networking disappears after reboot or fresh installation.

Environment & Reproduction

No Wi-Fi toggle, no nearby SSIDs, or adapter shown as unavailable.

Root Cause Analysis

Laptops with Broadcom, Realtek, or Intel chipsets on Ubuntu 20.04.

Quick Triage

Missing firmware, blocked radio state, or unloaded kernel module.

Step-by-Step Diagnosis

Run lspci -nnk, lsmod, and rfkill list to identify chipset and soft/hard blocks.

Solution – Primary Fix

Install correct firmware package, unblock radio, reload module, and restart NetworkManager.

Solution – Alternative Approaches

Confirm SSID list appears and stable DHCP lease is assigned.

Verification & Acceptance Criteria

Keep linux-firmware updated and avoid third-party driver conflicts.

Rollback Plan

Escalate if adapter is absent from PCI/USB enumeration entirely.

Prevention & Hardening

Revert to previous kernel and remove recently added DKMS wireless drivers.

Related Errors & Cross-Refs

Ubuntu Wi-Fi docs, linux-firmware package notes, and vendor driver guidance.

Related tutorial: View the step-by-step tutorial for Ubuntu 20.04 LTS.

View all Ubuntu 20.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Airplane mode can persist in firmware and requires rfkill unblocking.