Card detection very unreliable due to physical dimensions

[marcowidmer]

In our projects, we use the DM3AT microSD Card socket. It has a simple physical switch to detect the card:

Unfortunately, on the USBSDMux (both "classic" and "fast" variants), the PCB corner which triggers the card detection switch is cut off:

This results in very unreliable card detection, as it depends on the exact insertion angle. If not inserted perfectly, U-Boot reports MMC: no card present and fails to boot the kernel.