"No command" is an error message that can appear on Android devices that usually indicates an issue with the device's recovery mode. When an Android device is in recovery mode, the user can access various options to perform maintenance tasks, such as updating the device's operating system or wiping the cache partition. If the device encounters an issue in recovery mode, it may display the "No command" error message. This message usually means that the device was unable to complete a task in its recovery mode and provides instructions for the user to attempt to resolve the issue, such as restarting the device or performing a factory reset. It's important to follow these instructions carefully, as incorrect actions taken in recovery mode can cause further problems with the device.