Convert CSO to APK

An Android device or installer that accepts only APK can trigger this request when the source file is a CSO. The practical solution is to run the CSO in a PSP emulator or obtain an Android release; renaming or repackaging it does not convert the software.

What the CSO format is

CSO, also called CISO, is usually a compressed ISO disc image used for PlayStation Portable games and software. PSP dumping and compression utilities such as maxcso reduce the image size while preserving the PSP disc-image structure.

CSO files commonly appear when users back up UMD media, transfer PSP games, or load them in an emulator. The image normally contains PSP data and executable code, not Android application files. Because .cso is also used for some unrelated file types, verify the file's origin before processing it.

What the APK format is

APK is Android's installable application-package format. It is a ZIP-based archive containing an Android manifest, compiled code such as DEX files, resources, native libraries when required, and signing information.

Android's package manager can install an APK because the package contains software compiled for Android and declares its components and permissions. APK files can be installed outside Google Play when the device permits sideloading, although Google Play commonly distributes modern applications through app bundles that generate device-specific APKs.

A PSP executable inside a CSO cannot run as native Android code. Changing game.cso to game.apk, or renaming a decompressed ISO, produces an invalid or unusable Android package.

How to use the CSO on Android

1. Try the CSO directly in a PSP emulator. Install PPSSPP from its official distribution source or a trusted app store. Copy the legally obtained game.cso to the Android device, open PPSSPP, and select the image from its game browser. PPSSPP supports CSO as well as uncompressed ISO, so conversion may not be necessary.
2. Decompress the image only if required. On Windows, macOS, or Linux, install the open-source maxcso utility and run maxcso -d -o game.iso game.cso. The -d option decompresses the CSO and -o specifies the ISO output. Keep the original file until the ISO has been tested.
3. Copy and test the ISO. Transfer game.iso to the device and open it in PPSSPP. If the emulator supports the original CSO, the ISO generally offers no functional advantage; it is simply larger and uncompressed.
4. Inspect the image only to verify its contents. 7-Zip or another ISO-capable archive utility can help identify the image type after decompression. If an image unexpectedly contains an existing Android APK, extract that APK; it does not need conversion. A normal PSP image will contain PSP-specific files instead.

When an APK can be created

An Android developer can build an APK that bundles or launches a PSP emulator core, but that creates a new Android application rather than converting the CSO. It requires an Android Studio project, emulator integration, Android-compatible code, app signing, and legally distributable game data. Use Build → Generate App Bundles or APKs → Generate APKs in Android Studio to produce a development or release APK after the project is configured.

That wrapper does not turn PSP code into Android code, and embedding copyrighted game images may require permission. For an installable Android version of the game, obtain the developer's Android release instead.

Compatibility and conversion limits

Decompression changes only the container: game.cso becomes game.iso, while the PSP executable, architecture, controls, and dependencies remain unchanged. Emulator compatibility and performance vary with the game, device hardware, emulator version, graphics backend, frame-skip settings, and the image's compression.

No suitable online converter can translate an arbitrary PSP CSO into a functioning APK. Services claiming to do so cannot replace Android compilation and signing; uploading large game images also creates file-size, privacy, and copyright risks. Use local tools for decompression and a PSP emulator for execution.