Fixes for first-run and hardware issues: J-Link and nRF Connect SDK not detected, ESP-IDF and serial ports, provider errors, long sessions, the Register card.
Confirm the SEGGER J-Link drivers are installed and the board enumerates in nrfjprog --ids. Re-plug the board and reload the VS Code window.
Flash command fails
Make sure no other tool (nRF Connect for Desktop, OpenOCD) holds the J-Link interface. Only one process can flash at a time.
"nRF Connect SDK not detected" on the home
The header row names the state it actually found: not a display glitch, the toolchain check itself cannot see an SDK.
The full view names each platform's state and what to install.
Install the nRF Connect Extension Pack and, through its Toolchain Manager, an SDK and toolchain. Reload the window, or force a re-read with ↻ on the row. Still missing: the SDK lives under a path the nRF extension does not know about; point it there in the extension’s own settings, then reload.
Confirm ESP-IDF is installed and IDF_PATH is set in the environment VS Code launched from. The Espressif IDF extension sets this up; reload the window after installing it.
ESP serial port not found
Most ESP dev boards need a USB-to-UART driver, CP210x or CH340 depending on the board. Install it, re-plug the board, reload the window.
"No serial data received"
The port exists, the USB-UART bridge answers, but the chip behind it says nothing when esptool asks. The row names what it can see, the bridge, and never guesses the board behind a stock CP2102.
The exception in the row, and the detail behind why: the bridge named, the chip unconfirmed.
Check
If it is wrong
Is the port free?
A monitor is holding it. Close it and retry.
Is the board in download mode?
Hold BOOT while connecting, or move the mode switch.
Is it a Fanstel LEW840x?
The selector card must sit on ESP32, or the nRF is holding GPIO2 low. This board has no BOOT button.
ESP flash fails
Confirm the correct serial port and chip target are selected and the board is in download mode, then retry.
Verify your API key in the extension settings and that the endpoint URL matches your provider (for example https://openrouter.ai/api/v1 for OpenRouter).
Model refuses tool calls or returns plain text
The configured model must support native tool-calling. See Models for recommendations.
Long session hits a context or prompt-length error
The agent manages the context window itself and announces a compaction before it runs, keeping the goal, the board, the bug, and the open file. Still seeing it, update the extension; a fresh chat is cheap to start, since project memory briefs it.
First checkpoint is slow on a large repository
The first snapshot of a big repo takes a moment; later checkpoints are incremental and fast.
Cellular, satellite NB-NTN, nRF54 edge-AI basics and the LEW840x gateway firmware need a free account; everything above that group works without one. Click Register, sign in with GitHub or email in the browser, and come back to the same window: the card you clicked is open.
Still stuck?
Open a discussion. Include your platform, SDK version, and what the terminal printed.
