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Troubleshooting

Most problems fall into a few buckets: the computer can't reach the phone, a stray adb server grabbed USB first, sends fail with a permission error, or MMS needs the companion app. Work through these in order.

Phone won't connect

  1. Confirm developer mode and USB debugging are enabled on the phone.
  2. Unplug and replug the cable. Use a data-capable USB cable (charge-only cables are a classic gotcha).
  3. On the phone, look for the Allow USB debugging? prompt and tap Allow. If you previously denied it, revoke USB debugging authorizations in Developer options and try again.
  4. In dumbsms Settings → phone, click reconnect.
  5. Try a different USB port on the computer (hub ports can be flaky).

adb server blocking USB

dumbsms talks to the phone directly — it doesn't need the adb binary. But if Android Studio, another tool, or a background adb server is already running, it claims the USB interface exclusively and dumbsms can't get in.

  • Settings → phone shows ⚠ adb server is running when this happens. Click stop adb server.
  • Or from a terminal: adb kill-server
  • Toggle auto-stop adb on startup (on by default) so dumbsms clears the conflict every time it launches.

Message won't send

  • Check you're connected — the bottom-left status should say connected, not disconnected or connecting.
  • For a new message, dumbsms stays on the compose screen until send succeeds or shows an error inline. Read the error text before retrying.
  • If the error mentions permissions, on the phone try Developer options → Disable permission monitoring.
  • Plain SMS failures can sometimes be a wrong subscription id — the CLI accepts --sub 0 or --sub 2 if the default doesn't work.
  • Emoji in SMS may not work on all carriers/phones — a known limitation.

Pictures or groups not working

Almost always means the companion app isn't active:

  1. Settings → phone: if mode says adb-fallback, MMS not supported, install the companion app.
  2. Settings → companion app: status should be installed, not "not installed" or "upgrade available".
  3. If status shows upgrade available, click upgrade.
  4. On the TCL Flip Go, sideloading has extra OEM gates — see the companion app guide.

Stale or missing threads

  • Settings → cache → clear cache forces a full reload from the phone. Threads disappear immediately; they refill as sync runs.
  • If you cleared cache while disconnected, nothing reloads until you reconnect — that's expected.
  • dumbsms remembers the last phone you connected to and preloads its cache on launch, even before a live connection.

TCL companion install fails

If install reports insufficient storage but the phone has plenty of free space, it's the OEM sideload gate — not a real storage error. Make sure you're installing from dumbsms (which sets the required flags and uses the whitelisted package id), not a raw adb install of a differently named APK.

Full write-up: The one app this phone will install.

Sync or photo download feels slow

Some of this is normal — especially on the TCL Flip Go. In our tests the TCL moves data at roughly ~1.2 K/s over Bluetooth vs ~15 K/s on a Sonim XP3plus (~10× slower). First-time thread backfills and MMS photo pulls can take minutes, not seconds.

  • Stay on USB for the initial companion install and first big sync if you can — it's faster than BLE on any phone.
  • Watch the progress indicator near the thread list or attachment — it shows percent, speed, or bytes when available.
  • After the cache is warm, day-to-day texting should feel responsive even on the TCL; slowness is mostly bulk data transfer.

Still stuck?

Contact the author with your phone model, what you tried, and any error text from Settings or the compose screen.

Eyeing a flip we haven't tested? See phone compatibility — you can ship a new unit for testing (no guarantees; I keep the phone).