cara root T4, bisa buat yg i/yg biasa, nda masalah
ada 2 cara
1.pake linux, masuk ke adb,colokkan tablet, agan harus ngubah sistem OS bawaannya t4i, untuk melakukan hal ini,agan HARUS bener2 paham sistem pemprograman linux secara advanced, cari dan edit bhs pemprograman di bwh ini, dump image system dari t4 agan ke pc,trus edit

Dump all imgs from your current ROM
./dump_imgs.py stock_imgs
cp -a stock_imgs new_imgs

Rebuild boot.img
./rkunpack new_imgs/boot.img
mkdir -p new_imgs/boot && cd new_imgs/boot
gunzip < ../boot.img-raw | sudo cpio -i --preserve-modification-time --make-directories
# Edit init.rc
# Replace "mount cramfs mtd@system /system" with "mount ext3 mtd@system /system noatime nodiratime"
sudo find . ! -name "."|sort|sudo cpio -oa -H newc|gzip -n >../newinitrd.gz
cd ../..
./rkcrc -k new_imgs/newinitrd.gz new_imgs/boot.img

Rebuild system.img with ext3 and root
cd new_imgs
sudo cramfsck -x system system.img
# Add the su binary from androidsu.com/superuser/
wget downloads.androidsu.com/superuser/su-bin...3.2-efghi-signed.zip
sudo unzip su-bin-3.0.3.2-efghi-signed.zip system/bin/su
sudo chmod 6755 system/bin/su
sudo vi system/build.prop # Adjust ro.build.display.id to identify the ROM version
dd if=/dev/zero of=/tmp/system.img bs=1024 count=250000
mkfs.ext3 /tmp/system.img
tune2fs -i 0 system.img
mkdir -p /tmp/system
sudo mount -t ext3 -o loop /tmp/system.img /tmp/system
sudo rsync -av --delete system/ /tmp/system/
sudo umount /tmp/system/
cd ..

Write images
./img-manager.py write boot new_imgs/boot.img
./img-manager.py write system /tmp/system.img

Reboot the device
./rkflashtool b


yang ext3 mending diganti cramfs aja.. soalnya q pernah coba ext3 chipsetnya jebol.. kan rockchip asalnya pake cramfs.. kalo cramfs gak perlu rebuild boot.img. jadi cuma system.img yang di rebuild. untuk aplikasi img-manager.py dump_imgs.py rkunpack

editnya bisa pake notepad.

cara ke 2 karna lumayan panjang saya taruh di post bwh nya