Help, care and FAQ

Answers to common questions, how to look after your CAT, and a glossary.

Troubleshooting#

The screen is black but CAT is on

The backlight turned off after a while without input. Press any button or tap once to wake it; that first press does nothing else. Change the timing in Settings → DISPLAY.

CAT won't turn on

Plug it into a USB-C charger. A completely flat battery waits until it has charged enough before starting, which is quicker on a charger rated 1.5 A or more than on a computer port. Check the e-paper screen: Battery empty. means it needs charging. The power button does nothing while USB is plugged in.

I lost recent messages or settings

CAT saves only at certain moments (see how saving works). A reset or sudden power loss loses anything since the last save. Use POWER → SLEEP to switch off, and FORCE SAVE before updates.

My friend's CAT doesn't appear on the Nearby tab

Nearby only lists CATs heard directly over LoRa, not ones reached through the internet.
Ask them to press SELECT in Chat to announce, or open the Nearby tab themselves.
Both CATs must use the same radio settings.
If they are already a contact, they appear on Contacts, not Nearby.
You can always add them by address instead: START → Add LXMF address.

My message only has one tick

One grey tick means sent and waiting for a receipt. One tick with a dot means a propagation node is holding it for your friend, which is final and normal. Two green ticks only appear when your friend's CAT confirms delivery directly. See delivery marks.

"Messaging busy - try again"

CAT tracks one send at a time. Wait for the current message or doodle to finish.

My doodle shows as gibberish in Sideband

Doodles only display on CATs. Other LXMF apps show the raw doodle data as text.

The Dashboard shows 0.00

The sensors are still starting up; readings arrive within about a minute of switching on.

Crypto says "Baochip busy"

The crypto chip generates its keys for about 4 minutes after every start. Try again a few minutes later.

The Wi-Fi bridge stays on "connecting"

Check that Wi-Fi shows Connected to. CAT moves to another hub if one doesn't answer, and returns to the home hub later. You can pick a hub yourself in TCP BRIDGE.

Explore says "Not enough memory for Explore"

Press B to go back, then try again. Restarting CAT frees memory.

Care and safety#

Charging: charge at room temperature, indoors and out of direct sun. The charger doesn't monitor battery temperature.
SD cards: insert and remove only while CAT is off. Formatting erases everything.
Save before you unplug. Use SLEEP or POWER DOWN rather than letting the battery run flat, and don't reset during Saving....
Screen timeout: radios and sensors keep running while the screen is dark. Use POWER DOWN to switch CAT off, for example when flying.
USB accessories draw from CAT's battery. Turn the setting off when you are done.
E-paper keeps its last image without power. Faint ghosting between full refreshes is normal.
The speaker is a small buzzer and is loudest in the upper midrange; music sounds chiptune-like by design.

Updating the firmware#

Firmware updates use the CAT provisioner on a computer. It updates all four processors in turn, from a release package, over USB.

Save first: POWER → SLEEP and wake again, or DEVELOPER → CONTROLS → FORCE SAVE.
Connect CAT to the computer and run the provisioner with the release package. If several CATs are connected, select yours by serial number.
USB disconnects and reconnects several times during an update. Don't unplug until it reports success.

Your Wi-Fi networks, messages and contacts are kept.

The USB shell#

Connected to a computer, CAT's game processor offers a text console on its USB serial port (any terminal program, any baud rate). Press a key to get the prompt game:~$, then type help. Handy commands:

Command	Shows or does
`version`	The firmware version and build.
`lxmf address`, `lxmf address qr`	Your address (and a QR code drawn in the terminal).
`lxmf contacts`	List, add, rename or remove contacts.
`batt`	Battery and charger state.
`mesh`	Mesh roles, including `mesh pnsel home\|auto\|off\|<hash>` for the mail node.
`timezone`, `message tone`, `backlight`	The same preferences as Settings.
`usb`, `sd`	USB accessory mode and SD card state.

The shell isn't available while USB keyboard/mouse mode is on.

Older devices#

The documentation for the original µCritAir virtual-pet firmware (feeding, fishing, the apartment and arcade) is kept as the legacy µCritAir manual.

Glossary#

Address	Your CAT's 32-digit LXMF delivery ID.
Announce	A broadcast saying who you are and how to reach you.
FHE	Fully homomorphic encryption: computing on encrypted data.
Hub	A public Reticulum server CAT connects to over Wi-Fi.
LoRa	The long-range, low-power radio used between CATs.
LXMF	The messaging format used by Chat, Sideband and NomadNet.
Mail node	The propagation node that holds your outgoing mail for unreachable friends.
PN10	The number of particles up to 10 µm per cubic centimetre.
PM2.5	The weight of fine particles under 2.5 µm per cubic metre of air.
Propagation node	A Reticulum mailbox that stores messages for offline devices.
Reticulum	The encrypted mesh networking system CAT uses.
Transport node	A device that forwards other devices' traffic.