Pulling NAND flash content from device

[subver]

Hi, could someone explain me how can i download NAND content of my mk908 v5? Or just part of it, like "system" partition.
I use Windows XP PC. I've tried rkflashtool, but get message "cannot open device". (I have put device in flash mode with "reset" button. Other tools recognize device ok).
Rom Flash tool v1.37 doesn't have function of downloading, only flashes? But when flashing the process of verifications starts, so this tool can read flash? How can i read flash with this tool?

I need backup copy of my "system" partition for some experiments

[mitchell4you]

If you have basic skill of linux.. rkflashkit has a option to backup partitions (only for rockchip devices)
Https://github.com/linuxerwang/rkflashkit

There is rkdump and cwm
-see developer section

See