How to make microsdxc bootable?

Question

ASUS

There is a microsdxc flash drive for 256 gigs. There are 2 USB adapters for GINZZU GR-312B (USB 3.0) flash drives and another T-flash (micro SD)/M2 USB KS-is Doxy (KS-059)
I want to make a livecd on a microSD flash drive. In Windows, everything works fine, the flash drive is detected from both adapters. I recorded the image of 7ki. Both adapters are visible in the BIOS when connected. However, if you start booting from them, a standard error pops up that there is nothing bootable on this device. As if he sees the adapter, but does not see the flash in it. How to be, share your experience or assumptions.