From my experience: even when you have full Android sources for the device (vendor blobs for camera/modem notwithstanding) it is PITA to do something out of the

From my experience: even when you have full Android sources for the device (vendor blobs for camera/modem notwithstanding) it is PITA to do something out of the ordinary. Want to enable hotspot on boot? Few dozen lines in Java or a shell script sending keyboard commands to open the particular settings page and enter to toggle the setting. Want simultaneous wifi client and modem? Good luck fighting with connection manager service automatically setting up routes. Use UART? Better hope that guys configuring the clock tree have explicitly made sure the UART clock is gated, instead of UART receiving the clock from something else by accident.