Debian 13 on a ZWO ASIAIR Plus
Flash the first-gen ZWO ASIAIR Plus CM4, the model built before ZWO moved to Rockchip, with the ready-made OpenAstro image. A guided script backs up the stock ZWO OS, writes the image to the internal eMMC, and can restore stock later.
THESE INSTRUCTIONS WILL NOT WORK ON ZWO ROCKCHIP DEVICES. For those, see ZWO ASIAIR Plus (RK3568).
Flash with the guided script
The ASIAIR Plus's OS lives on the CM4's 32 GB eMMC, reached over USB. The flash scripts in the openastro-zwo-asiar-plus-cm4 repository handle the whole workflow on Linux, macOS, and Windows: they install rpiboot on first use, back up the stock ZWO ASIAIR OS, download and flash the latest OpenAstro image, and can restore your stock backup later if you want to go back.
To put the ASIAIR Plus into flashing mode you need three things connected at once, as shown below: short the boot pads with a paperclip or jumper wire, a USB-A (computer) to USB-C (ASIAIR) data cable, and 12V DC power. Unlike some other devices, the ASIAIR Plus does not power up from the USB cable alone.
Then clone or download the repository and run the script. On Linux and macOS:
cd flash
./openastro-flash.sh
On Windows, run flash\openastro-flash.ps1 in an Administrator PowerShell.
Both give the same menu:
1) Backup - save the stock ZWO ASIAIR OS from the eMMC (do this first!)
2) Flash - write the OpenAstro image to the eMMC
3) Restore - write a stock backup back to the eMMC
Run Backup before you flash. The saved stock ZWO ASIAIR OS is your only way back to the original software, and the script's Restore option writes it back whenever you want.
Everything the old manual guide covered is baked into the image: the 12V DC outputs are live from power-on, the Renesas USB firmware is preinstalled so the USB 3.0 ports work out of the box, and the OpenAstro jingle plays on the built-in buzzer once the device is up, so you know it's ready without a screen.
The stock Raspberry Pi OS kernel ships with HIDRAW enabled, and the image bakes in a udev rule granting device access, so ZWO EAF focusers and EFW filter wheels should work out of the box.
Connect to the device
The image comes up with these defaults:
| Setting | Value |
|---|---|
| Hostname | openastro |
| Username / password | astro / astro |
| WiFi access point | OpenAstro-XXXX (2.4 GHz), password 12345678 |
| WiFi AP address | 172.24.1.1 |
| Ethernet | DHCP |
| 12V power ports | On at boot |
XXXX is the last 4 hex digits of the device's WiFi MAC address (for example
OpenAstro-915D), set automatically on first boot so multiple devices at the
same site each get a unique hotspot name. The access point starts at every
boot, so even if the device can't be reached over your network you can always
join its hotspot and log in at 172.24.1.1.
Connect over Ethernet or join the OpenAstro-XXXX WiFi network, then SSH in.
Use one of the following SSH clients depending on your operating system:
- Linux: Terminal (built-in)
- macOS: Terminal (built-in)
- Windows: MobaXterm (or PuTTY, or Windows Terminal)
ssh astro@openastro
Change the default password right away, then update the operating system:
passwd
sudo apt update && sudo apt full-upgrade -y && sudo reboot
Join your own WiFi network (optional)
Change all WiFi settings from the AlpacaBridge web page: open
http://172.24.1.1:6800 while joined to the hotspot (or
http://openastro.local:6800 from your LAN) and use the WiFi card on the
Server tab to scan for networks, join one with its password, and manage the
hotspot's name, password, and band. No command line needed.
The hotspot runs on its own virtual interface, so joining your home WiFi does not take down the hotspot. One radio, one channel: while connected as a client, the hotspot follows the client network's channel. You can also just use the Ethernet port.
AlpacaBridge Comes Preinstalled
The image ships with AlpacaBridge 3.5.1 (with the WiFi manager) already installed from the OpenAstro APT repository and running as a systemd service, so the device works at a dark site straight from the flash. No internet required and nothing to install.
The web portal listens on port 6800: http://openastro.local:6800 from
your LAN, or http://172.24.1.1:6800 when joined to the hotspot.
Keep AlpacaBridge up to date
Updates arrive through apt from the OpenAstro repository. Check
apt.openastro.net to see the latest AlpacaBridge
version and whether your device needs an update. Whenever the device has
internet access, pull the latest release with:
sudo apt update
sudo apt install alpacabridge
This upgrades AlpacaBridge to the newest version even if the image bundled an
older one. Running sudo apt full-upgrade as shown above also picks it up
along with the rest of the operating system.
Continue to Configure AlpacaBridge to set up your devices. If you ever need to reinstall the service manually, the steps are in Install AlpacaBridge.
Restore the stock ZWO software
Run the flash script again and choose Restore to write your stock backup back to the eMMC. This is why the backup step matters: it is the only way back to the original ZWO ASIAIR software.