How to Turn Your Old Android Phone Into a 4K Dashcam

Most Android phones have plenty of camera to work with as a dashcam. The real problem is that Android, and especially the manufacturer-customized versions of it on Samsung, Xiaomi, Huawei, OnePlus, and others, is aggressive about killing apps it thinks are draining battery in the background. A dashcam that gets silently stopped ten minutes into a drive is worse than not having one, since you won't find out until you need the footage. These settings fix that.

1. Update Android and check storage

Update to the latest Android version the phone supports. Then check available storage, several hours of 4K footage adds up fast, and loop recording needs headroom to work with. Clear old photos, apps, or downloads you don't need on a phone that's now dedicated to recording.

2. Exempt the app from battery optimization

This is the step that matters most on Android. Go to Settings → Apps → Dashoo → Battery and set it to Unrestricted (the exact wording varies: "Don't optimize," "No restrictions," or similar, depending on your Android version). By default, Android treats background apps as battery drains to be killed off, which is exactly what happens to your recording session if you skip this.

3. Check manufacturer-specific autostart settings

Stock Android's battery settings aren't the whole story if your phone runs a manufacturer skin. These add their own, separate battery management layer on top:

• Samsung: check Settings → Apps → Dashoo → Battery, and also look for "Put unused apps to sleep" under Battery and device care, make sure Dashoo is excluded.
• Xiaomi (MIUI/HyperOS): enable Autostart for the app in Settings → Apps → Permissions → Autostart, separate from the standard battery optimization setting.
• Huawei: check Settings → Battery → App launch, and switch Dashoo from automatic to manual management so you can allow auto-launch, secondary launch, and running in background.
• OnePlus (OxygenOS): check Settings → Battery → Battery optimization, and separately, Advanced settings for any per-app background activity restriction.

If you're not sure whether your phone has one of these extra layers, search "[your phone model] autostart permission" or "[your phone model] background app battery settings", manufacturers change menu wording often enough that exact paths go stale fast.

4. Grant camera, microphone, location, and storage permissions

Install Dashoo from Google Play and grant every permission it asks for on first launch. Denying location, for instance, means no GPS speed overlay, not a smaller version of the feature, but no feature at all.

5. Mount it and connect power

A basic windscreen or dashboard suction mount works fine. For power, use a USB-C car charger, or micro-USB if it's an older device. As with any phone, continuous 4K recording drains battery fast on its own, expect roughly 90 minutes unplugged. Keep it on a charger for anything longer.

6. Start recording

Tap record before you pull off. GPS speed and location, plus G-force readings, log automatically. If something happens, tap once to flag the clip so loop recording doesn't overwrite it later.

If recording still stops unexpectedly

If you've done all of the above and the app still gets killed mid-drive, check for a persistent notification setting, Android usually keeps a foreground-service app alive as long as its notification stays visible, and some phones let you separately disable notifications for an app in a way that also kills its foreground service. Make sure Dashoo's recording notification is allowed to show.