I’m trying to increase the default value of the Enterprise form fileupload field size from 1 MB to 5 MB
I found that under eforms:fileupload JCR node
which is being built from the storage when starting hippo, and I can change that value by modifying it in storage\repository\nodetypes\custom_nodetypes.xml, but that change will be overridden when the storage is rebuilt.
where I can change that value and my change remains permanent?
You should not make changes in that file, or in general anywhere directly in storage. Each storage directory is local to a node.
The default seems to be defined in the cnd. Off the top of my head I can’t think of a nice way of doing this. You could of course checkout the project and recompile it with a larger default.
You can create a reusable field group. Then you can change the default from there.
In any case I suggest filing an improvement issue.