Here is an Android 4.2.2 Jelly Bean rooted firmware for the PiPO M8HD (aka Max-M8HD) RK3188 based tablet with 10.1" display. This custom firmware is based on latest official update published on 2013/09/24. 

( M8HD_update#305_OTA1.0.0_20130924.img )

Build information:

Kernel: Linux version 3.0.36+ (root@alex-System-Product-Name) (gcc version 4.6.x-google 20120106 (prerelease) (GCC) ) #305 SMP PREEMPT Tue Sep 17 16:31:14 CST 2013

Android 4.2.2 JB: rk30sdk/rk30sdk/rk30sdk:4.2.2/JDQ39/eng.root.20130923.175205:eng/opinions-on-teclast-p90hdst-keys

ro.rksdk.version=RK31_ANDROID4.2.2-SDK-v1.04.00

Custom firmware features:

• root with latest SuperSU version 1.65 (free version)
• removed most Chinese and unnecessary applications
• Google Play Store fixes so more application are visible/compatible
• updated busybox v1.21.0.git (2012-11-29)
• Unix like init.d boot scripts support, more details on init.d scripts here
• changed permissions on external sdcard to allow write access
• increased space for applications (/data partition) to 4 GB
• NEW! kernel modules (cifs, tun, lan, serial, xpad) compiled by Oma & Crew RKTablets, thank guys!
• optional ClockworkMod (CWM) Recovery easy install package

Notes: 

- Certificate Center and original PiPO launchers have been kept in the firmware

- Certificate Center will ask for product key, which is not needed, just hit later and connect to Internet and it will be activated

- any update received thru OTA may interfere with our custom firmware, please let us know how it goes if you try such updates

Download: kasty-pipo-m8_hd-422-ota_100_20130924-rooted4.zip

Flash with Rockchip Batch Tool version 1.7, use Restore button.

Please report any problem with this firmware, I can't verify this custom firmware works as I don't have a PIPO M6 pro tablet to test the custom firmware.