Download Android ICS 4.0.4 firmware for Cube U19GT 3G tablet from here or from here. Download another Cube firmware from here.
Archive name: u19gt-3g
Archive file size: 192 MB
Model: Cube U19GT 3G tablet / U19GT_3G
Platform: Rockchip RK3066
FW version: 4.0.04
Boot version: 1.16
Build number: U19GT_3G rk30sdk-eng 4.0.4 IMM76D eng.root.20121212
SDK version: V1.01
Caution: Please do not update firmware unless you know what you are doing, you really want it or it is absolutely necessary. Firmware updates may occasionally have bad results, like bricking your device, temporarily or permanently. The firmware update process is done entirely at your own risk. Before attempting to update the firmware, back up your data.