How to boot a Dell Inspiron laptop from an SD card

Hi,

I have a Dell Inspiron 7520 laptop (1 year old). I would like to install a second OS on an SDHC card and use it for some occasions. I was not able to boot this laptop from a bootable SD card which works just fine on other laptops (HP, Samsung, Gateway). It seems that only Dell laptops have a problem with that. They don't seem to treat SD cards as bootable devices. The laptop sees the card just fine otherwise (so the card reader is functional, and the laptop can read and write files to the card). Is there any way (e.g. a BIOS update) to actually make this work? Well, except buying an SD to USB external adapter.

Appreciate any suggestion in advance. Thanks.