Rikomagic just release their beta Android 4.2 firmware for their MK802IV quad core model.
Geekbuying has mirrored the firmware here:
https://www.dropbox.com/s/9e5sm6qogdqqnjx/IV%20update%20FW0522.rar?m
password is geekbuying.com
and the firmware upgrade instruction is also in the package. please make sure to update with the rkflash tool, don’t support micro sd card update.
Also some bugs which found in this rom:
1 Netflix still don’t work in the Android 4.2 tv stick, so if you want Netflix working,please stick on the Android 4.1 OS;
2 Bluetooth keyboard and headphone can’t work well. this is also a well-known problem for rk3188 base tv stick,and still need to wait factory to update;
3 USB Camera still don’t support, again,it’s a rockchip problem, should wait for the update.
But you will get higher antutu score after you upgrade to android 4.2
Custom firmware with root and other goodies posted at
http://www.arctablet.com/blog/forum/rockchip-rk3188-android-mini-pc/rikomagic-rkm-mk802iv-android-4-2-2-custom-root-firmware-version-20130523/