/overlay folder read-only problem despite mounting it to write mode ?!

[eightkiller]

Hi, I usually have no problem mouting / or /boot partitions to be able to write or add or replace some files inside (with mount -o remount,rw / for example), but I wanted to do the same with the /overlay folder (mount -o remount,rw /overlay), the command seems to work, but impossible to replace things, it is still in read-only mode. What should I do to be able to do so ? The folder seems to work differently.

Thanks in advance for your help