USB endoscope not detected on Android? Check the OTG switch

A USB endoscope that shows no reaction at all when plugged in — no prompt, no sound, nothing on Magic Endoscope’s connect screen — is usually a phone-side setting, not a broken probe. Many Android phones keep USB host mode, commonly called OTG, switched off until you turn it on, and a smaller number of phones cannot run it at all.

What OTG is and why it matters

USB OTG (On-The-Go) is the mode that lets a phone act as a USB host — supplying power and reading data from an attached device such as your endoscope — rather than only being a USB device itself, the way it is when charging from a computer. Some Android phones expose a dedicated switch for this mode, off by default, so plugging in a probe before turning the switch on does nothing. Magic Endoscope shows “USB OTG Not Available” when the phone reports no USB host support at all, and “No Endoscope Found” when host mode is available but nothing is currently enumerated on the port. The fix is different for each, so check which message you are seeing before you continue.

Find the OTG switch

1. Open your phone’s Settings app and search for “OTG” — most phones with a manual switch surface it in search, even though the menu path varies by brand and Android version.
2. On Xiaomi, Redmi, and POCO phones (MIUI or HyperOS), it’s under Settings → Additional settings → OTG. Turn it on before plugging in the probe: on these phones the switch can be greyed out and unavailable while any USB device, including a charging cable, is already connected. It also switches itself off again after about 10 minutes of inactivity, so enable it right before you connect, not in advance.
3. On Huawei and Honor phones, look for an “OTG connection” or “USB OTG” toggle under Settings → Battery or Settings → System & updates; the exact location depends on the EMUI or HarmonyOS version.
4. On Samsung phones, older One UI versions list OTG under Settings → Advanced features, or Settings → Connections → More connection settings. Many newer Samsung phones enable host mode automatically and show no switch at all.
5. Reconnect the probe once the switch is on, and allow Magic Endoscope’s USB access prompt if Android shows one.

If detection succeeds but the picture later drops every time your screen locks, that’s a separate Xiaomi/HyperOS behavior, not this switch — see Xiaomi HyperOS disconnects the USB endoscope when the screen sleeps.

Some phones cannot run OTG at all

USB host support depends on hardware and firmware, not only a setting. If Magic Endoscope shows “USB OTG Not Available,” Android itself is reporting that the phone has no USB host feature — no switch or setting changes that on this phone. This affects some budget phones and tablets, and occasionally a phone whose manufacturer left the feature out of specific regional firmware even though similar models support it. Check your probe in the compatibility list, and if a phone you expected to support USB accessories still fails, confirm host mode against its published specifications or test the same probe on another phone or a computer.

Confirm the probe is detected

Reopen Magic Endoscope’s connect screen, or tap Rescan if it was already open. “USB Camera Detected” means the switch fixed it — open the live preview and point the probe at a lit, nearby object to check that the image changes as you move it. If the screen still reads “No Endoscope Found,” check the cable and adapter next; a charging-only cable will not carry the video connection, and the USB endoscope setup guide covers the rest of that checklist.

If it’s still not detected

If this started right after a phone update rather than with a brand-new setup, also see endoscope shows a black screen after an update. Otherwise, send product support your phone model, Android version, probe model, and connection type. Include whether Settings shows an OTG switch at all, and its state when you plugged in. If you have access to another phone or a computer, note whether the same probe is detected there — that separates a phone-side limitation from a probe or cable problem.