Mounting an SD card automatically, without blocking system start when missing?

I wish to auto-mount an SD card onto my Debian (command-line only).

To have this, I have added this to /etc/fstab:

/dev/mmcblk0p1          /media/sd       auto    defaults,user,umask=000 0 0

This works great, IF the card is presented during boot. Otherwise it will block the booting.

What I wish is to make:

  • the system capable booting without the SD card (/media/sd is empty)
  • the system capable booting with the SD card (/media/sd is mounted)
  • when system booted without SD card, and later gets one inserted, mount it automatically
  • when an SD card is umounted (manually), and later a new one inserted, mount it automatically

How could I tune the fstab to reach this functionality?