OTA Update Guide

The authoritative OTA documentation lives in docs/MANUAL.md, section 12 “Firmware updates” — this page is just a quick recipe.

Requirements

• Device running v1.6.2-beta or newer. Every earlier build shipped a defective applier that reported success without installing anything (see MANUAL §12 “Read this first”); older devices must be flashed over USB once.
• The simut_vX.Y.Z.bin from the GitHub release page — not the .uf2 (that one is for USB/BOOTSEL flashing).
• An admin session on the device’s web server.

Steps

1. Log in (cookie SIMUTSESS)

NONCE=$(curl -s http://<device-ip>/api/login_init | jq -r .nonce)
PASS_HASH=$(echo -n '<password>' | sha256sum | cut -d' ' -f1)
curl -s -c cookies.txt http://<device-ip>/api/login \
     -d "user=admin&pass=$PASS_HASH&nonce=$NONCE"

2. Stage the image

curl -s -b cookies.txt \
     -F "file=@simut_vX.Y.Z.bin" \
     "http://<device-ip>/api/restore?op=stage&commit=1"

Takes about 30 s for a ~1 MB image — do not power off. The response must report "v":0 and "committed":1 before apply will do anything.

3. Apply

curl -s -b cookies.txt -X POST http://<device-ip>/api/ota/apply

Answers 202 and the device reboots. If it answers 503 “Display in use”, retry after a few seconds.

4. Verify

Read the firmware version back from /api/status or from the display. Never infer success from timing or HTTP codes alone — the only proof of an installed update is the new version reporting itself.

What survives, what doesn’t

A config snapshot carries Wi-Fi credentials, users and sensor slots across the apply. The LittleFS filesystem — history, language packs, calibration — is REFORMATTED by the apply. Take a backup first (web file manager → Backup).

Network note

If uploads on port 80 stall on your network, some routers kill long port-80 flows; using an alternate HTTP port works around it.