Here is an Android 4.2.2 Jelly Bean rooted firmware for the PIPO M6 (model without 3G) tablet based on latest official update from Pipo released 2013/07/31

( update_M6_NO 3G_chinese_20130731.img )

Build information:

Kernel: Linux version 3.0.36+ (root@alex-System-Product-Name) (gcc version 4.6.x-google 20120106 (prerelease) (GCC) ) #49 SMP PREEMPT Sat Jul 27 11:25:03 CST 2013

Android 4.2.2 JB: rk30sdk/rk30sdk/rk30sdk:4.2.2/JDQ39/eng.ljh.20130704.112304:eng/opinions-on-teclast-p90hdst-keys

Stock firmware revision history:

• Google Search Bar overlay while screen is changing to vertical position.
• 3G Network will automatically disconnected after sleep.
• Change ddr to 600MHz

Custom firmware features:

• root with latest SuperSU version 1.51 (free version)
• removed most Chinese and unnecessary applications, removed Certificate Center asking for product key
• 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

Download: kasty-pipo-m6-422-20130731-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 tablet to test the custom firmware.  

Thanks tzutolin for the tip