[petecox]

AFAIK, there's at least 3 kernels running on an Android device. - LK (1) for the bootloader (the screen you see when launching fastboot, I believe) - LK (2) for 'Trusty', the crypto engine - Linux as the bootloader's payload.

If Magenta is also an instance of LK then they can maintain each through a common source tree and the bootloader can initialize the device resources once without needing separate drivers for each distinct kernel.

[swetland]

Most Android devices also run some OS on the baseband processor (on-die or separate), and often the Wifi, Codecs, Bluetooth, Power Management blocks, etc also run their own little OSes. It's getting a little crazy, how many distinct cores exist on these devices.

Magenta was based on LK but it is definitely its own thing and is evolving in its own directions (64bit, SMP, userspace, etc). LK is generally MCU-targeted and can be very tiny (15-20K for a minimal system used for bootloader cores or tiny embedded things).