I wrote these directions for Linux, but you can easily adapt them for WIndows(except installing adb and fastboot) by just removing 'sudo' from the commands.
Download and extract the following to your home directory: http://dl.dropbox.com/u/6529005/Fuhu...om_scratch.zip
Open a terminal(ctrl+alt+t) and run the following command to install ADB and Fastboot (Universe).
sudo apt-get install android-tools-adb android-tools-fastboot
We will flash the new TWRP recovery image using fastboot:
sudo fastboot flash recovery recovery.img
Now the device is in TWRP, choose Wipe>Factory Reset>Slide to Wipe
We will now push the WiFi Fix that might be needed to restore wifi.
sudo adb push fuhu_nabi2_wifi_fix.zip /sdcard/fuhu_nabi2_wifi_fix.zip
adb push fuhu_nabi2_v1912_system.ext4.win /sdcard/TWRP/BACKUPS/___YOUR_DEVICEID_GOES_HERE__/oem/system.ext4.win
Once this step is finished you can Home>Reboot>Bootloader in TWRP.
Now your device is back to version 1.9.12, from here you can start doing your OTA updates, but before you do that, we have to go back to the original recovery image, otherwise the OTA will fail.
Lets flash the original recovery image:
sudo fastboot flash recovery nabi2_original_recovery.img
If your system needs the wifi fix, you can flash the fuhu_nabi2_wifi_fix.zip in TWRP>Home>Install>fuhu_nabi2_wifi_fix.zip