====== Getting in (root / ADB) ======

  * The head unit joins the home Wi-Fi and is reachable over the network. **adbd runs as root.**
  * There is **no usable USB-ADB port** — the exposed USB port is a //host// port (5 V out, reads
    FAT32 sticks). The SoC's device/gadget port is not exposed. So all access is over **TCP/ADB**.
  * The on-device terminal app runs as **uid 1000 (system)**, and there is **no working ''su''**.
    So **network ADB is the only path to root** — re-enabling it is the key to everything.

===== Re-enabling network ADB after a reboot =====

adbd is a disabled init service, started only by a USB-config trigger, and it reads its TCP port
**only at startup**. From the uid-1000 terminal you set the ADB TCP port and then **cycle the USB
config** (''sys.usb.config'' none → adb), which restarts adbd and makes it bind the TCP port. This
is **not persistent** across reboots — it must be redone after each boot (or automated by a
system-signed app).

===== Updating apps in place (keeping their data) =====

The ROM is signed with the standard Android **test-keys**, which equal the local debug keystore.
So debug builds can legitimately claim ''sharedUserId="android.uid.system"'' and **update installed
apps in place without losing their settings** — the signatures match. This is what lets a
self-built app run with system privileges (needed for the cluster overlay and CAN access).