I bought a Ninebot MAX G30 E II three years ago, in May of 2022. I broke the folding hinge release button within days of buying the scooter. Turns out that if you yank the lever without sliding the button several times and with enough force, the plactic button will split in half. I asked if I can buy a replacement button, but either the service center or the manufacturer (can't remember which) replied that they won't sell me the part and instead I should have shipped the scooter to them for the repair. Yeah right. I modeled a copy of the button and milled a replacement out of aluminum and it has been working great ever since. Here is the file as an STL.