Bootlog Uptime is a free debug utility application developed by MuMu21 for Android devices. The app provides information about when your phone started up and shut down, making it useful if you suspect your phone is rebooting and you want to know when it does. The app also has an optional root permission feature that copies /proc/last_kmsg when a crash is detected.

One notable feature of Bootlog Uptime is that it requires permission to save the kmesg logs to an SD card. However, using root permission is completely optional, and if not checked in preferences, it does nothing. The app is easy to use and provides accurate information about your phone's uptime.

If you encounter any problems with the app, the developer encourages users to email them instead of giving a one-star rating, giving them a chance to help you. Overall, Bootlog Uptime is a reliable debug utility that can help you keep track of your phone's performance.