> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lagerdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Version 0.51.0

> September 28, 2026

## <u>Upgrade Notes</u>

* **Update your boxes.** The new flash and erase checks, the probe lock and the diagnosis run on
  the box. Run `lager update --box <box-name>` after you upgrade the CLI. A 0.51.0 CLI still
  works with an older box, and judges the flash from its output text.
* **`flash` and `erase` can now fail where they reported success.** On J-Link, a flash that
  programmed nothing now exits 1 with `Flash failed:`. An erase that erased nothing exits 1 too.
  A script that relied on exit 0 will now stop at the real failure. Fix the cause that the
  output names, then run the command again.
* **J-Link must show evidence of a flash or an erase.** A flash needs a `J-Link: Flash download:`
  line (or `O.K.`) after `Downloading file`. An erase needs `Erasing done.`. If your target's
  J-Link output does not contain these lines, set `LAGER_JLINK_REQUIRE_EVIDENCE=0` in the CLI's
  environment.
* **`lager debug NET gdbserver` exits 0 on a box whose gateway cannot tunnel.** Version 0.50.2
  exited 1 there, even with `--no-tunnel`. The command now starts the GDB server, prints a
  warning, and exits 0. It prints no address, because no debugger on this machine can reach the
  server. A script that must know this can read `"gdb_port_reachable": false` from `--json`.
* **A second operation on one probe now waits.** A `connect`, `memrd`, `reset`, `flash` or
  `erase` that arrives during another one on the same probe waits for it to finish. After 300
  seconds it fails with `Debug probe <serial> is busy`. Set `LAGER_PROBE_LOCK_TIMEOUT_S` on the
  box to change the limit.

## <u>Features</u>

* **A failed J-Link flash tells you what else happened.** `Diagnosis:` lines list every other
  J-Link program that used the probe during the flash. On a DA1469x, they also tell you if the
  target reset during programming, and which reset it was.
* **`LAGER_JLINK_REQUIRE_EVIDENCE=0`** turns off the evidence check for a target whose J-Link
  output uses different wording. The CLI sends it with each flash and erase. A failure line still
  fails the command.
* **`gdbserver --json` reports `gdb_port_reachable`** as `false` when no debugger on this
  machine can reach the GDB server.

## <u>Bug Fixes</u>

* **`lager debug NET flash` printed `Flashed!` when J-Link programmed nothing.** J-Link prints
  `Downloading file` before it downloads the RAMCode that programs the flash. When that download
  failed, the CLI still counted the flash as done. The erase before the flash cleared the part, so
  the target stayed blank. The CLI now reads J-Link's failure lines first, and
  requires J-Link's evidence of a flash.
* **The cause: a second J-Link client on the probe.** J-Link lets two programs open one probe,
  and it does not stop them from interfering. The Lager Box ran a flash and a `connect`,
  `memrd`, `reset` or Python script on the same probe at the same time. The box now runs one
  operation per probe at a time.
* **A probe that another program held gave a false success.** J-Link answered
  `Selected interface (SWD) is not supported by the connected probe.` and exited normally. Both
  `flash` and `erase` then reported success with nothing written or erased. They now fail on
  that line.
* **A J-Link that dropped off USB during a flash gave a false success.** The box discarded the
  error and returned no output, and the CLI printed `Flashed!`. The flash now fails with
  `JLinkExe exited mid-session:` and the last line that J-Link printed.
* **A flash that failed on a DA1469x still reset the target.** The box no longer resets the
  target after a failed program, and it no longer prints `Target reset` over a failure.

## <u>Known Limitations</u>

* **On an nRF5340 with J-Link V9.50, a plain `erase` does not erase.** J-Link prints
  `Erasing done.` with `Erase: 0.000s`, and the flash does not change. A range erase with
  `--erase-start` and `--erase-size` works. See
  [issue #618](https://github.com/lagerdata/lager/issues/618).
* **A J-Link verify failure does not fail the flash.** A DA1469x reports a false
  `Verification failed` on a correctly programmed part, so the CLI ignores these lines. See
  [issue #617](https://github.com/lagerdata/lager/issues/617).
* **The probe lock orders requests, not whole commands.** A `memrd` that you start during a
  flash can run between its erase and its program step, and read the erased flash.

## <u>Installation</u>

To install this version:

```bash theme={null}
pip install lager-cli==0.51.0
```

To upgrade from a previous version:

```bash theme={null}
pip install --upgrade lager-cli==0.51.0
```

Then update your boxes:

```bash theme={null}
lager update --box <box-name>
```

## Resources

[View Release on PyPI](https://pypi.org/project/lager-cli/0.51.0/)