Running Specter-Desktop locally and connect to BitcoinCore on your node via Tor is indeed by far the easiest method, especially now that Specter-Desktop has Tor-client built-in (i.e. one-button install through Specter).
However, I was curious to the HWI-bridge option as well and it is actually pretty easy to setup. Here are the steps (I’m on MacOS so perhaps some of the details differ for other OS’es):
When I mention ‘local Specter’ I mean Specter running on your laptop/desktop, not the Specter app running on your node, the latter acting as remote Specter
- Connect your local Specter to Specter running on Umbrel, by doing the following in your local Specter:
Preferences > select Yes, I run Specter remotely > in the URL field enter http://umbrel.local:25441/.
Restart specter on your local and afterwards you should see that it is connected to Bitcoin Core (through specter on your Umbrel node).
- On your local specter go to
settings > usb-devices and select Custom URL. In the field, enter http://localhost:25441/hwi/api/
- Access your device bridge settings (the link is mentioned on the usb-devices page of step 3) and assure that it contains the following domains:
- Click on ‘Test connection’, plugin your hw-device and Specter should be able to detect your device.
FYI the above assumes connecting your hw-device to your local machine/laptop. As @lukechilds mentions, at this moment there is no way that specter running in Umbrel is able to detect usb-devices which are plugged directly in to your node. I guess technically it could be possible by passing either the --device or --device-cgroup-rule flag in the docker config for Specter, but you would need to know the device id upfront and pass it to these flags.