MultiSystem is a powerful tool for locked- and unlocked-bootloader Android devices with many features that at least includes the following:
- Keeps stock system partition safe/rooted
- Permenant root survival with proper use
- MultiROM support via virtual ROMs
- Unlimited number of virtual ROMs
- Booting options to choose stock, primary, or secondary virtual ROM
- Any of the virtual ROMs can work as a recovery replacement
- Flashing multiple ROMs at the same time without a reboot
- Ability to create/install ROMs on Linux to microSD card
- Great performance & battery life on virtual ROMs
- Recovery solution to install ROMs or Mods
- Easy upgrade to newer versions of Android
- Ability to safely apply OTA updates to virtual system
- Permissive SELinux and other kernel tweaks
- Safe flashing that doesn't trip KNOX flag on Samsung devices
- Wrapper script runs via ADB or a Terminal Emulator on device
- APK to manage all MultiSystem functions with a nice UI and extra options
- Management for the best performance & user experience
- Support for all Android devices with microSD card
- Portability to almost all devices
- Compatibility with all Android versions
More information can be found here.