A commonly cited download for the CVD1810-WJ firmware can be found on this Shared Google Drive .
Official firmware links for these generic units are rarely hosted on a single manufacturer site. Instead, they are often shared via community repositories and cloud storage: cvd1810 firmware link
The refers to the Microcontroller Unit (MCU) software used in many "unbranded" or universal Chinese Android head units. Specifically, the CVD1810-WJ version is a common identifier for devices running on platforms like the AC8227L. A commonly cited download for the CVD1810-WJ firmware