TurtleBot 4 Standard stuck in headless mode (shows "unknown" IP) after Wi-Fi setup failure on ROS 2 Jazzy

[Mahadev2917]

Robot Model

Turtlebot4 Standard

ROS distro

Jazzy

Networking Configuration

Simple Discovery

OS

Ubuntu 24.04

Built from source or installed?

Installed

Package version

Official TurtleBot 4 ROS 2 Jazzy SD Card Image (latest release)

Type of issue

Networking

Expected behaviour

When Wi-Fi credentials for the lab network are configured via AP mode (or via turtlebot4-setup), the TurtleBot 4 should successfully connect as a client to the target Wi-Fi network, obtain an IP address, display the IP on the OLED screen, and allow SSH connections from the companion PC.

Alternatively, if connection to the client network fails or times out, the robot should gracefully revert to Access Point (AP) mode so that network credentials can be reconfigured.

Actual behaviour

1. After entering lab Wi-Fi credentials during AP mode setup, the robot reboots into client mode but fails to connect to the network.
2. The OLED screen displays the IP address as "unknown".
3. Instead of falling back to AP mode, the robot remains stuck in client mode ("headless" state with no accessible network interface), making SSH access impossible.
4. Attempting to connect to a mobile hotspot causes it to continuously reboot or fall back into AP mode unexpectedly.
5. Prior to this connection lockout, the robot experienced severe sensor transmission latency and time synchronization mismatches during localization/mapping attempts.

Error messages

No terminal logs accessible via SSH due to lack of network interface/IP.
OLED screen status:
- Wi-Fi IP: "unknown"
- Device stuck in client mode without falling back to AP mode.

To Reproduce

1. Flash a fresh official TurtleBot 4 image for ROS 2 Jazzy / Ubuntu 24.04 onto the Raspberry Pi 4 SD card.
2. Power on the robot and connect to its initial Access Point Wi-Fi network.
3. Configure the target Wi-Fi network (lab Wi-Fi) credentials via the setup interface and apply settings.
4. Allow the robot to reboot into client mode.
5. Observe the OLED screen: the IP displays as "unknown", the robot cannot obtain an IP via DHCP, does not accept SSH, and does not revert to AP mode.

Other notes

• Reflashed the SD card multiple times with the official ROS 2 Jazzy TurtleBot 4 image, but the issue reproduces consistently.
• At one point, an IP address briefly appeared, but incoming SSH attempts timed out / were refused.
• This robot is borrowed under an academic deadline at IIT Bombay, so any recovery steps (e.g., manual netplan recovery via mounting the SD card on another PC) would be greatly appreciated.