You might also try inserting/removing the cart around 30-40 times to scrape off a thin layer of metal so it's fresh on both the cart and the Game Boy.

weird. try cleaning the metal contacts on the pcb with 99% isopropyl alcohol, electronics contact cleaner, or worse case a pencel eraser to see if it maybe just has dirt / film gunk on it.

I’ve tried different Gameboys, or even placing insides of the cart into classic game case(gray), but it's still not working:(

I'd suggest trying another gameboy to make sure its the cart and not the cart jack on the gameboy. If its the cart, I'd probably just find a decent cart that works and replace its guts with the guts of the usbcart, and of course alter/cut the casing for the usb jack.

Hello guys,
I’m writing to tell you that I have a problem with the bleep bloop cart. The problem is that it stopped working some time ago. When I turn on my gameboy it displays a corrupted Nintendo sign. However, I’ve noticed that when I insert a thick piece of paper between the cart and the gameboy it works completely fine. I had this issue before and back then I’ve decided to dismantle it, and put some tape from the back of the PCB, this kept the cart working. For some reason it needs more tightness for the cart to work. Unfortunately, it happened again and this time I had to use duct tape to hold the cart in my gameboy as tight as possible! Has anyone encountered something like that before? Does anyone know what’s the solution to this problem? Funny, because EMS cart has its connectors placed lower and it works without any issues.

http://img535.imageshack.us/i/dsc00249jb.jpg/