# Hendi remote-control lockout findings

Firmware under test: **v1.12** (`getSoftwareVersion()` / `I?`+`V?` via
`components/actor/hendiCtrl.py`). Reproduced and verified on real hardware
using `scripts/hendi_ctrl_app.py`'s `--trigger-error-state`, `--reset` and
`--test-heater` flags.

## Trigger

Calling `remoteEnable(True)` (`R1`) and then disconnecting/exiting without a
matching `remoteEnable(False)` (`R0`) - i.e. an ungraceful disconnect while
remote control is enabled - puts the device into a locked-out state.

## Recovery attempts

| # | Recovery method | Mechanism | Result |
|---|---|---|---|
| 1 | `--reset` (toggle DTR/RTS reset line) | Soft reset via serial control lines, no power loss | **Fails** - `remoteEnable(True)` still returns `HendiException("Communication error")` on the next connection |
| 2 | `--reset` immediately followed by `--test-heater` in the *same* process/connection | Soft reset, then reuse the still-open serial connection | Succeeded once, but not reproducible across repeat isolated attempts - not a reliable recovery path |
| 3 | Physical power cycle (device knob) | Full power-off/on of the unit | **Recovers** - `remoteEnable(True)` succeeds immediately afterward, heater sweep runs cleanly |

## Symptom while locked out

- `I?` / `V?` (software identifier/version queries) still respond normally.
- `R1` (`remoteEnable(True)`) fails with a communication error - this is the
  only observed symptom, and it blocks any command path that needs remote
  control enabled (e.g. `--test-heater`).

## Conclusion

On firmware v1.12, only a physical power cycle clears the lockout; neither a
serial soft-reset nor a fresh serial reconnect does. This is the behavior the
planned firmware fix should address - a graceful-disconnect timeout, an
explicit unlock command, or making the DTR/RTS reset line actually clear the
lockout flag.