Android's Wireless debugging is deliberately ephemeral: the listener dies
when you leave the settings screen or the device sleeps, and it picks a
new random port each time. In one session it offered 35545, then 40401,
then 43781, and vanished entirely twice. Every deploy therefore started
with tapping through Settings and reading a port off the screen.
enable_persistent_adb.sh waits for any such transient window, then uses it
to pin adbd to port 5555 - the port deploy.sh has always assumed - and
installs a Magisk service.d boot script so the same happens on every boot.
The phone is on DHCP with no reservation, so the script identifies it by
MAC rather than trusting a hardcoded address: a ping sweep populates the
neighbour table and the address is looked up there. That beats a router
reservation because it needs no router access and works on any network.
One bug worth naming: the first version took the first `device` line from
`adb devices`. Pairing also leaves an mDNS _adb-tls-connect._tcp entry for
the same phone, so it reported port 5555 as reachable while nmap showed it
closed. It now matches the exact ip:port.
Verified: nmap showed 5555 closed then open across the switch; a run
against a deliberately wrong IP reported "phone moved" and connected; and
after `adb reboot` the script connected with no arguments and no
interaction, with /proc/uptime at 149s and service.adb.tcp.port reading
5555, so the boot script really ran. shellcheck clean.
Trade-off accepted by the user: adbd on a fixed port is reachable to
anything on the LAN, though it still requires an authorised key.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
