Privacy Policy — CRMT for Android (com.mythosia.crmt)
Effective Date: 2026-11-07
Contact: support@mythosia.net
1. Overview
CRMT is a USB serial monitor for Android, made by Mythosia ("we"). You connect a USB serial cable to your phone with a USB OTG adapter, pick the device and tap "Connect". CRMT then shows the data the device sends and lets you send commands to it.
CRMT works entirely on your phone. There is no login or account, no ads, no analytics and no crash reporting, and the app does not communicate with our servers or any other server. Through the app, we do not collect or receive any of your data, and we do not sell or share any data.
This policy covers the CRMT Android app (package name com.mythosia.crmt). It does not cover other Mythosia apps or CRMT for other platforms such as Windows. In the app, this policy opens from Settings > About > Privacy policy.
2. Data We Collect
None. CRMT does not send any data off your phone, so we never receive information about you, your phone, your devices or how you use the app.
To work, the app handles the following on your phone only:
- Data exchanged with your device: the data your USB device sends and the commands you send to it. It is shown in the log on your screen, kept only in the app's memory, and never saved to storage or sent anywhere (see section 4).
- USB device details: for each USB device plugged into your phone, its USB vendor ID, product ID and product name, and for a supported adapter its chip type (FTDI, CP210x, CH34x, PL2303 or CDC). CRMT uses them to list the device or show that it is not supported, to pick the right driver and to remember your settings for it. CRMT does not use or store a device's serial number.
If you contact us by email (outside the app), we use your email address and your message only to answer you.
3. Data Stored on Your Phone
CRMT saves only the following, in its private app storage on your phone. Other apps cannot read it.
- Recent devices: one entry for each USB serial adapter you have connected (up to 50). An adapter is identified by its USB vendor ID and product ID (plus the port number on adapters with several ports); these name the adapter model, not your individual unit. Each entry holds the device name you gave it, its chip name (for example CH340), its serial settings (baud rate, data bits, parity, stop bits, flow control, DTR and RTS), the send format (text with a line ending, or HEX) and when you last used it. CRMT saves this automatically when you connect, so the device is ready with the same settings next time.
- Quick commands you create (up to 32): label, command, format (text or HEX) and line ending.
- App settings: theme, "Show timestamps", "Keep screen on while connected" and whether the log is shown as text or HEX.
- Two technical values: the screen you last had open (so CRMT can return you to the log if Android rebuilds the app's screen) and whether CRMT has already asked for notification permission (so it asks only once).
In detail, these are stored as three small files (profiles.json, quick-commands.json and app-settings.json) in the app's private files folder, one value in the app's private preferences and one value in the private storage of the app's built-in web view.
Android backup: if backup is turned on for your phone (for example Google backup), Android may include these saved settings in its automatic app backup and restore them on a new phone. That backup is handled by Android and your backup service (for example your Google account), not by us, and we cannot access it. The log is never in a backup, because it is never saved to storage.
4. Data Exchanged with Your Device
- The data you receive from your device and the commands you send are kept only in the app's memory, so that they can be shown in the log. Only the most recent lines are kept (about 100,000 at most); older lines are dropped.
- The log is never written to your phone's storage and never sent anywhere. CRMT has no button to export or share it. If you select text in the log and copy or share it with Android's text selection menu, it goes only where you choose.
- After you disconnect, or if the cable comes out, the log stays in memory, so you can still view it while the app is running (Last connection > View log). If you connect again, new lines are added to the same log. "Clear" removes the lines from the log screen. Cleared lines are not shown again, and they stay in memory only until newer lines push them out or the app is fully closed.
- The log is completely erased from memory when the app is fully closed, for example when you tap "Force stop" in Android settings, when you restart your phone, or when Android closes the app in the background. Swiping CRMT away from the recent apps screen ends the connection, but Android may keep the app, and the log, in memory for a while.
- While you are connected, the notification shows the device name, the amount of data received and the connection settings, but not the data itself. Depending on your phone's lock screen settings, it can also appear on the lock screen.
5. Permissions
- USB device access (USB host): when you tap "Connect", or when you plug in a supported cable and open CRMT from Android's prompt, Android asks whether CRMT may use that USB device. CRMT uses this access only to communicate with the device you choose: to receive its data, send your commands and apply your serial settings. When the device is unplugged, Android ends the access and asks again the next time you plug it in, unless you chose to always open CRMT for that device.
- Notifications (POST_NOTIFICATIONS, Android 13 and later): for the notification shown while you are connected, which has a "Disconnect" button. CRMT asks once, right after your first successful connection. If you don't allow it, the connection still works; only the notification is not shown.
- Foreground service (FOREGROUND_SERVICE and FOREGROUND_SERVICE_CONNECTED_DEVICE): keeps the USB connection running, so CRMT keeps receiving with the screen off or while you use another app. It runs only while a connection is open. It stops when you tap "Disconnect" in the app or in the notification, when the cable is unplugged or the connection is lost, or when you swipe CRMT away from the recent apps screen.
- Internet (INTERNET): CRMT is built with .NET MAUI, and its screens run in Android's built-in web view (Android System WebView). This permission is part of the framework's standard app setup. CRMT does not use it: all screens are packaged inside the app, the app makes no network requests, and its web view allows only the app's own pages and blocks connections and pages from anywhere else.
- com.mythosia.crmt.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION: an internal permission that Google's AndroidX library adds automatically and that only CRMT uses. It makes sure that only CRMT can deliver its own internal messages, such as the result of a USB access request. It gives no access to your data.
CRMT does not ask for access to your location, contacts, photos or files, camera, microphone or phone identifiers.
6. Sharing and Third Parties
- We do not sell, share or transfer any data, because we do not receive any.
- CRMT contains no advertising, analytics or crash-reporting SDK, and no other third-party SDK that collects data. The open-source components it is built with (for example .NET MAUI, usb-serial-for-android and React) run only on your phone. Their licenses are listed in the app under Settings > About > Open-source licenses.
- Google Play handles downloading and updating CRMT under Google's own privacy policy. If Android System WebView on your phone is missing or too old to run CRMT, the app shows an "Update" button that opens the WebView page in your phone's app store (usually the Google Play Store app). CRMT turns off Android System WebView's usage metrics for the app. If you have chosen to share usage and diagnostics data with Google, Android and Google Play on your phone may still send Google crash and diagnostic data, including data about CRMT, under Google's privacy policy. Google may then show us crash and performance statistics for CRMT in Google Play Console. CRMT itself does not collect or send this information.
7. Retention and Deletion
- Saved settings stay on your phone until you delete them:
- Remove a device: on the Devices screen, under Recent devices, tap a device that is not plugged in, then tap "Remove from recent". The list shows the 10 most recently used devices.
- Delete a quick command: open it for editing and tap "Delete".
- Delete everything CRMT has saved: in Android Settings > Apps > CRMT > Storage, tap "Clear data" (names vary by phone), or uninstall CRMT.
- CRMT keeps the 50 most recently used devices and removes older ones automatically.
- If Android has backed up CRMT's settings, that copy is kept and deleted by your backup service (for example your Google account) under its own rules.
- The log is kept only in memory and is erased when the app is fully closed (see section 4).
- We receive no data from the app, so there is nothing to delete on our side.
8. Security
CRMT's saved settings are in its private app storage, which Android keeps separate from other apps. The log is kept only in memory. Because CRMT itself sends nothing over a network, no data from CRMT is exposed in transit.
9. Your Choices
- Turn CRMT's notifications on or off at any time in Android settings. The connection works either way.
- If you chose to always open CRMT for a USB device in Android's prompt, you can undo it in Android Settings > Apps > CRMT (for example "Open by default" or "Set as default"; names vary by phone).
- Remove saved devices and quick commands in the app, clear CRMT's data or uninstall it (see section 7).
- Choose whether app data is backed up in your phone's backup settings.
10. Children
CRMT is a work tool for USB serial devices and is not directed to children. It does not collect personal information from anyone, including children.
11. Changes
We may update this policy from time to time. Updates will be posted on this page with a new effective date. If a future version of CRMT collects or shares any data, we will update this policy before that version is released.
12. Contact
For questions about this policy or about how CRMT handles data, email support@mythosia.net. Developer: Mythosia (product.mythosia.net).
