[Q] How to deactivate wipe in zip ROM topic

Hi!

The main thing I am looking for, is how to make a zip version of a ROM stop erasing everything from the previous version and only update it.

More details about why I need this, below:
I have a SMARTQ Z Watch and the latest official ROM v3.7 no longer has the remote camera function. It was deleted starting with version 3.2, so 3.1 must have been the last to have it.
If I install an older version, which has the remote camera function, it works, but updating to latest always wipes absolutely everything from the phone, including any apps and files installed manually.
Unfortunately, the remote camera function is not an apk that I can find in the system/app folder, so it must be somehow else build in the ROM. I have no idea how to locate it.

Any help to this request would be highly appreciated.

this is the latest 3.7 ROM http://d2.smartdevices.com.cn/files/...3.7/update.zip
this is one of the older versions, which has the remote camera function included http://d2.smartdevices.com.cn/files/...2.5/update.zip