http://www.arctablet.com/blog/forum/arnova-9-g2/please-help-cant-entering-recovery-flashing-mode-on-the-tablet/
Have a look here

On here it says and i quote "insert a paperclip in the Reset pinhole of the tablet and press the Menu button"

http://www.arctablet.com/blog/featured/flashing-arnova-g2-rockchip-2918-rockchip-flashing-tool/

In the end it is about having the will to look.

You can use also adb/opinions-on-teclast-p90hdrminal if you have root on the tablet

with adb, adb reboot bootloader

with terminal, reboot bootloader

check the post number 50
http://www.arctablet.com/blog/forum/arnova-9-g2/arnova-9g2-custom-firmware-upgrade-to-android-40-ics-google-play-full-root-and-face-unlock/page-4/ by vadim537

I think is not about the tablet, is just a mistake in pressing the right keys in the right order.

also here another method http://www.arctablet.com/blog/forum/arnova-9-g2/arnova-9g2-custom-firmware-upgrade-to-android-40-ics-google-play-full-root-and-face-unlock/page-5/

i am using adb to get the rockchip tablets in the flashing mode (if they are in working state)

Here is a tutorial
http://www.arctablet.com/blog/devices/arnova/adb-and-fastboot-tutorial/
On how to install and configure the pc to get it right.

The first question is:
Does your tablet work ? For example can you go to settings and enable usb debugging ?
If yes, you will have to install the drivers and then use adb like this:
adb devices -----> this will verify if you device is connected, if you get any kind of response it is perfect, if you don`t get nothing you need to find the proper drivers
adb reboot bootloader ------> this will reboot the tablet in the flashing mode and a new window should pop-up with the instalation of rk29 drivers, those drivers can be found in the rockchip tools pack

If your tablet is not working and you see the dead android with the exclamation sign.
-connect the tablet to the pc
-install the drivers
-use adb like above