Updating firmware

Once a camera runs this firmware, you update it with a signed .camfw package. No programmer or cable is needed.

First build a release image with a newer version than the camera runs, and sign it.

What is kept#

An update rewrites only the rootfs partition. The DATA partition is never touched, so these stay:

• settings (cam.conf);
• users and passwords, and the recovery code;
• SSH keys and the SSH host key;
• the camera’s CA and certificate, so your browser keeps trusting it.

The camera reboots at the end. Video stops for about 1 to 2 minutes.

From the web UI#

You need an admin account.

1. Open System (https://<camera-ip>/ui/system).
2. Under Firmware update, choose the .camfw file and click Upload and check.
3. The camera checks the package and shows the result: the installed version beside the new version, the device, the signer and the size. Nothing is installed yet.
4. Tick Yes, install this firmware and reboot the camera, then Install. Only the admin who uploaded it can install it. Discard throws it away.
5. Reload the page after about 2 minutes.

Limits:

• The page needs its script (/ui.js). Without scripts, use SSH.
• Packages up to 5 MiB. Larger ones go over SSH.
• The web UI refuses packages signed with --allow-downgrade.
• An upload not installed within 15 minutes is discarded.

Over SSH#

You need an SSH key on the camera.

Check first. This changes nothing:

ssh root@<camera-ip> camupdate --check < build/update/<version>.camfw

A good package prints a line like:

camupdate: OK: version <version> for MCA40E-IFADO, <bytes> bytes, signed by <key>

Then install:

ssh root@<camera-ip> camupdate < build/update/<version>.camfw

The SSH session shows the progress while the camera writes. Then the camera reboots and the connection drops.

What camupdate checks#

Before it writes anything, camupdate refuses a package unless:

• the header’s signature is from a key in the image’s /etc/cam/update-keys (security-key signatures must carry the touch and PIN flags);
• the device is MCA40E-IFADO and the partition is rootfs;
• the image’s SHA-256 matches the signed header, and it is a squashfs that fits the partition;
• it is not a bench image;
• the version is newer than /etc/cam/version.

Downgrades#

An older version is refused unless the package was signed with --allow-downgrade (see Signing and update keys). Install those over SSH only.

If an install fails#

• Any failure before the write starts changes nothing. The camera keeps running.
• During the write camupdate stops every other program and feeds the hardware watchdog itself. If the write or the read-back fails, it tries again, up to 3 times. If none succeeds it logs INSTALL FAILED and reboots. A power cut during the write has the same result.
• In that case the camera won’t boot our firmware. Write the rootfs partition back from your flash backup with the CH341A programmer (see Installing), then install again.

Check the result#

After the reboot, the web UI’s Status or System page shows the new version. Over SSH:

ssh root@<camera-ip> cat /etc/cam/version

A camera that reboots gets a new SSH session but keeps its host key, so ssh doesn’t warn.