Bug Radicale 2 images syncronization

Have on a "Turris Omnia" Radicale 2 running unfortunately the images syncronisation of the CardDav contacts does not work.
Find this github issue from 2017:

Unfortunately I lack the skills to implement this workaround on OpenWRT. Can someone help me with this, or offer a viable alternative?

find /overlay -name vcard.py
vi /the/location/of/the/file

Unfortunately, I cannot find such a file on the OpenWRT system.

The /Overlay folder is completely empty for me.

A "find / -name *.py" also finds nothing that can be associated with radicale.