@wallenjimmy
According to:
https://github.com/Hagb/decryptBooxU...ment-704006389
You can generate an example download link for your device:
http://data.onyx-international.cn/api/firmware/update?where={"buildNumber":0,"buildType":"user"," deviceMAC":"","lang":"en_US","model":"Nova3Color", "submodel":"","fingerprint":""}
Inside, you will find a link to the latest available .upx file (under "DownloadURLlist").
However, AFAIK Nova3Color came with the most recent Onyx Boox firmware (3.1?) stock, and there were no further updates.