Link concept: forum.xda-developers.com/t/allwinner-a33-firmware.3987273/ – Contains a "Downloads" tab with multiple stock ROMs.
(User: Xyauto / Pass: 123456) host firmware for various Chinese Android platforms. Online Cloud Update zq8003 android update link
If you obtain a manual update file (usually around 1.2GB), follow these steps: Link concept: forum