Trying to get a PC to boot off a bootable SD card that is inside an USB attached Android device

First, I'd like to make myself look less a madman than I may have appeared to be. I wanted to have a bootable USB stick with me at all times, but it's less convenient because it's an extra object and it's easier to lose, forget etc. Then I thought, I have an Android phone, and it has a micro SD in it; perfect. Not all PC's can boot off a card reader, but the phone itself **is** a card reader when attached as a disk drive. Or at least so I thought. Turns out that my netbook BIOS (tested on Asus eeePC) refuses to see it as an external harddrive; it only recognizes it as a generic USB device and doesn't offer an option to boot from it. The device has a name "Android phone" or smth, so it seems to me that it doesn't work as a "pure" card reader, and instead still manifests itself as a phone. Can it be somehow overridden?