The RK3188 (often referred to as the PX3 in car head units) was a popular quad-core processor that famously extended its lifecycle through firmware updates. While official support for Android 5.1 ended in early 2018, "exclusive" custom firmware remains the primary way users keep these legacy devices functional today. Performance & User Experience
RK3188 NAND chips degrade over time. Open a terminal (or ADB) and run: su -c fstrim -v /data Run this weekly to prevent the device from turning into a "laggy mess." rk3188 android 51 firmware exclusive
: NuPlayer becomes the default streaming player, and there is improved low-latency audio support for better performance in professional audio apps. Android 5.1 Update - PUMPKIN CAR STEREO SUPPORT CENTER Android 5