The way UEFI loads image files differs per firmware (and sometimes firmware version). On some devices all you need to do is drop a LOGO\Logo.bmp file into the E

The way UEFI loads image files differs per firmware (and sometimes firmware version). On some devices all you need to do is drop a LOGO\Logo.bmp file into the ESP, on others you need to flash a modified firmware image. The latter requires a lot more permissions than the former, of course, and with firmware downgrade protection, flash-based attacked should only work right after a new firmware has been released (or if you choose not to update your firmware for whatever reason). The authors seem to imply that there are semi-standard ways of loading user-supplied images in UEFI firmware, and I'm kind of interested in how they achieve this without reflashing the motherboard's firmware.