# adom-usb-stub-samd21

**adom-usb firmware device-test pack — Microchip.** BOSSA-flash stub firmware to a SAMD21/SAMD51 (Arduino Zero class) to enumerate as MSC, HID, CDC, or MIDI.

```bash
adompkg install adom-usb-stub-samd21
```

## Personas

| id | flashes | enumerates as |
|---|---|---|
| `msc-disk` | Mass storage | Mass storage |
| `hid-keyboard` | HID keyboard | HID keyboard |
| `cdc-serial` | CDC serial | CDC serial |
| `midi` | USB-MIDI | Audio/MIDI |

Chips: samd21, samd51 · flash method: `bossac`.

Once installed, `adom-usb` shows a **Flash ▾** persona picker on matching devices. Pick a persona, the pack flashes the stub, and the device re-enumerates as that USB class so you can mount / test / sniff it. This package ships the flash **contract** (a reference template) — drop your real signed firmware artifacts in `firmware/<persona>.<ext>` and publish your own version. See the adom-usb wiki page → *Writing a packet-sniffer plugin* (firmware packs share the same lifecycle).


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*Hero image: device photograph sourced from [Wikimedia Commons](https://commons.wikimedia.org) under its respective Creative Commons license. This is an open-source reference plugin for [adom-usb](https://wiki.adom.inc/john/adom-usb); manufacturers shipping their own device-test pack should supply their own product imagery.*