openSUSE installation on SD-card

today i tried to install openSUSE Leap 42.1 on a SD-card. I used a USB stick as installation medium. So far everything has gone well. The installation finished without any problems.

Then I went to the Bios to select the SD-card as Boot Option #1. But I couldn't find the SD-card there!

What do I have to change in order to make the SD-card appear in the BIOS?

Thanks for your help!