Hmmmmmmm that is probably the worst piece of so-called tech that ever came out of Dahon. It was the subject of a recall.

Those 2 screws need Loctite as others have recommended. But beware that there are 5 or 6 screws in that abortion of a latch that can and will work loose, each of which can send you tumbling. They all need Loctite.

Your safest option is to get rid of that POS and replace with a later version. For a tech-savvy person, it is OK but for the average customer, no.